EHS provides best practices and guidance for safely working with common chemicals/substances, this may also include but not limited to storing, handling and disposing of the chemicals/substances. If you do not see guidance for a particular chemical/substance you are working with or concerned about, please contact EHS, environment@mit.edu or 617-452-3477.
Aqua Regia is a fresh mixture of hydrochloric and nitric acids used to etch metals and clean glassware. It is very corrosive to skin and respiratory tract.
It needs to be mixed fresh for each use and evolves gasses which have caused many accidents and container ruptures. It should be used only when absolutely necessary. For detailed use instructions, you must develop your own standard operating procedure for your process by reviewing the Aqua Regia Chemical Factsheet.
Asbestos is a naturally occurring mineral fiber extensively used in building materials from the 1930s until the 1970s. It is resistant to heat, mechanical stress, and water. Asbestos fibers are only a hazard when they become airborne and can be inhaled.
Learn more about the Asbestos Program
Beryllium metal and its alloys are used in a wide variety of industrial products because they are light and resistant to heat, stress, and strain. Beryllium is highly toxic to the lungs and is a confirmed human carcinogen. All procedures that may be an exposure hazard should be evaluated by the EHS Office to insure that air concentrations are within acceptable levels. The ACGIH TLV for beryllium is 0.05 ug/m3. The OSHA PEL is 0.2 ug/m3.
All employees with potential for exposure can enroll in the annual medical surveillance program sponsored by the MIT Health Department.
For additional information about safe work practices (including use of a respirator, gloves, clothing, etc), consult the MIT Beryllium Program and Procedures.
The inhalation of dust, fumes, or mists containing beryllium or beryllium compounds present a very serious health hazard. Laboratory processes that can produce fumes or inhalable dust include heating, grinding, and machining of beryllium and its alloys.
In humans, beryllium causes both acute and chronic lung disease and lung cancer. Acute beryllium disease has been seen after brief exposures to soluble beryllium compounds. Symptoms range from a mild inflammation of nasal passages to bronchitis and lung inflammation.
Chronic beryllium disease is characterized by lung fibrosis (scarring) and inflammation, causing breathlessness upon exertion, weakness, chest pain, enlarged heart, and ultimately death. Beryllium has been documented to cause lung cancer in industrial beryllium production facilities. Beryllium can also cause allergic skin reactions.
To work safely with beryllium, all labs and shops must do the following:
- All procedures that potentially generate beryllium particulates, such as heating or machining or aerosols of beryllium salts, must be evaluated by the EHS Office to insure that air levels are safe.
- All researchers working with beryllium in a manner that creates airborne exposure can enroll in the Beryllium Surveillance Program at MIT Health by calling (617) 452-3477. The program is voluntary and free.
- Standard operating procedures for specific operations should be established before working with beryllium and its compounds. These will normally include the use of fume hoods or local exhaust ventilation.
- Prior to working with beryllium, employees must receive training from their supervisor. Beryllium users must also complete either Chemical Hygiene or Hazard Communication training and Managing Hazardous Waste training.
The following resources and detailed information is referred to in the Cryogen Safety web course (certificate required).
Best practice for dispensing liquid from a low pressure container to a dewar:
- Don a face shield and safety glasses, cryogenic gloves, long pants without cuffs, closed-toed shoes, and a laboratory coat.
- Next connect a transfer line to the liquid valve, if one is not already present, making sure the fittings match. Please note that the valve will be labeled. The transfer line should have a phase separator attached to reduce turbulence and the release of gas while filling.
- Check the pressure in the cylinder. It should read approximately 22 pounds per square inch. Position the Dewar on the floor at the base of the cylinder, or on some other support below waist level and insert the transfer line into the Dewar. The end of the transfer line should extend to the bottom, or just off the bottom, of the Dewar. Keep bystanders at least four feet away while filling in case of splashing.
- Open the liquid valve one half to three quarters of a turn to begin cooling down the transfer hose and adding the cryogen to the Dewar. The warm hose and Dewar will vaporize the cryogen as it cools and this could create splashing particularly if it is added too quickly. The pressure in the container will drive the liquid out through the valve.
- Once the hose and Dewar have cooled, open the liquid valve to obtain the desired rate of flow. However, if you fully open the valve, be sure to close it a quarter turn. A fully opened valve may freeze in that position causing a spill. A good flow rate is typically evident by a moderate vapor trail coming from the mouth of the Dewar. Listen for the change in sound as the Dewar fills – a higher pitch indicates the Dewar is getting full.
- When full, close the liquid valve. Remove the transfer line but be careful not to drop it or allow the phase separator to hit a solid object which will cause it to break. Watch out for any cryogen that continues to spill out of the transfer hose. Finally, place the top on the Dewar, pushing it all the way on and then pulling it up so that it is loose.
Best practice for dispensing gas from a high pressure container to equipment or system:
- Don cryogenic gloves, safety glasses, long pants without cuffs, closed-toed shoes, and a laboratory coat.
- Check the pressure in the cylinder. It should be approximately 230 pounds per square inch, but this will vary with the gas dispensed.
- Next connect the inlet of a suitable regulator to the gas use valve or a transfer line from this valve to an appropriate wall mounted regulator. Please note that the gas withdrawal valve will be labeled. The regulator should be designed for use with cryogens and adjustable over the desired pressure range.
- The outlet of the regulator is connected to the system receiving the gas using the appropriate transfer line – in this case it’s a dedicated gas line.
- Next close the regulator valve and open the gas use valve. Adjust the gas regulator to deliver the gas at the desired pressure, for example, 90 pounds per square inch. At this point you may begin withdrawing gas.
- In applications where large volumes of gas will be withdrawn from the container, the pressure building valve will be opened. This valve operates an internal circuit that allows more liquid to vaporize then would naturally occur through evaporation alone. The vendor supplying the container generally knows your application and opens or closes this valve when delivered.
The transportation of cryogenic containers in elevators represents a potential asphyxiation risk if researchers become trapped in an elevator with a container of cryogen. If a passenger elevator must be used, the first person rolls the container into the elevator, posts a clearly visible sign that warns staff and students not to enter the elevator. The first person pushes the elevator button for the appropriate floor and immediately gets off the elevator. The second person meets the elevator, removes the container and the sign.
This table lists the change in volume as the gas transitions from liquid to gas at room temperature. The resulting pressure that would be generated inside a container from trapped liquid under these conditions is also listed.
Helium | Nitrogen | Oxygen | CO2 | |
---|---|---|---|---|
Boiling point °F (1 @atm) | -452 | -321 | -297 | -108 |
Change in volume as liquid expands to gas at room temperature (liquid-to-gas expansion ratio) | 780 | 710 | 875 | 790 |
Pressure generated from trapped liquid allowed to warm to room temperature | 10,950 psig | 10,230 psig | Not Specified | Not Specified |
Note 1: Although CO2, which has a slightly higher boiling is technically not cryogenic liquid but has similar properties and is often included in this category. (Note: Source Argonne National Laboratory)
Resources / Additional Information
- LN2 Ice Cream Safety Plan Template
- Cryogenic Liquids SOP (certificate required)
- Cryogen Valve Diagrams
- Cryogen Safety Web Course Narrative
- Safetygram – Helium
- Safetygram – Oxygen
Cyanide salts (sodium and potassium) have a white crystalline or powder appearance. They are highly toxic by inhalation, ingestion, and can even be absorbed through the skin. As little as 50 mg can be fatal to a human being. Mixing dry salts with atmospheric moisture or with acids can release poisonous hydrogen cyanide gas which can be fatal.
MIT Procurement will not allow you to purchase cyanide salts unless the EHS Office approves your order. You must review and follow all the Cyanide Salts Safety Guidelines.
Formaldehyde is classified by OSHA as a Particularly Hazardous Substance, a probable carcinogen, and a respiratory and skin sensitizer. It has a strong odor detectable at 0.04 to 1 parts per million (ppm). The OSHA 8 hour Permissible Exposure Limit is 0.75 ppm. The 15 minute Short Term Exposure Limit is 2 ppm.
Formaldehyde can be used safely provided that the following precautions are followed:
- Use in a fume hood or other ventilated enclosure such as a dissection hood or ventilated downdraft table unless very dilute or small quantities.
- Wear gloves with good resistance to formaldehyde, such as the disposable nitrile Best NDex glove – Latex gloves provide short term splash resistance only and should generally not be worn for formaldehyde work.
- All formaldehyde waste should be collected and disposed of as hazardous waste.
- The Chemical Hygiene Lab Specific Training for your lab should cover formaldehyde hazards and safe use practices.
- Call the EHS Office (617-452-3477) if you can smell formaldehyde during your procedures.
- Make an appointment with the MIT Health Department (617-253-4481) if you experience any symptoms of eye, nose, or throat irritation during your work with formaldehyde.
MIT must identify all laboratory activities that are above the OSHA action level or short term exposure level (STEL) through initial air monitoring and provide training, medical surveillance, and engineering and work practice controls if air levels warrant it. The Industrial Hygiene Program (IHP) in the EHS Office has performed extensive air sampling for formaldehyde during a variety of lab activities such as animal perfusion, dissections, and tissue fixation and found the results to be below OSHA levels provided that suitable exhaust ventilation is used.
With proper exhaust ventilation, you should not detect any odors from formaldehyde work nor experience any symptoms of exposure such as eye tearing or throat irritation. If you do, please contact EHS immediately at (617) 452-3477 for an evaluation.
EHS sends a questionnaire annually to laboratory EHS Representatives to survey formaldehyde use and conducts air sampling of procedures where there may be a potential for exposure. Notify EHS for an evaluation if your procedures change and you work with large quantities of formaldehyde, perform animal perfusions, or do extensive tissue dissection work.
Hydrofluoric acid (HF) is a particularly hazardous substance, like many acids, but has added dangers that make it especially dangerous. It is less dissociated than most acids and deeply penetrates the skin. Symptoms of exposure may be delayed for up to 24 hours, even with dilute solutions. HF burns affect deep tissue layers, are extremely painful and disfiguring. The highly reactive fluoride ion circulates throughout the body and can cause multiple organ toxicity, including heart arrhythmias and death, if not treated.
Any suspected exposure to HF should be immediately flooded with water, decontaminated with calcium gluconate gel, and receive medical attention immediately. To do so, call 100 from a MIT phone or 617-253-1212 from a cell phone. An alternative response for an exposure may be indicated in a written SOP only after consultation with EHS and MIT Health.
All laboratories using HF must have unexpired calcium gluconate decontamination gel on hand. You may obtain it from the EHS Office by completing this form.
Calcium Gluconate Gel Request Form
All personnel are required to be trained by the EHS Office before beginning work with HF. The training covers safe use, personal protective equipment, and decontamination procedures.
To register or complete the training via the web, visit MIT Atlas (certificate login required) and follow these steps:
- Search for and select the Learning Center.
- Under the My Profile tab, click the “Create EHS Profile” or “Update PI / Activities” button.
- Select “Save and Continue.”
- On the Select Your Activities page, scroll down to the Chemical Safety section. Check the box for “Use or work in the area that store or uses hydrofluoric acid.”
- Click the “Submit” button at the bottom of the page.
- Options for completing the training will appear under the My Training Needs tab. This training can be completed via a classroom training or web course.
Isoflurane is an anesthetic gas that is widely used at MIT. Isoflurane is a halogenated anesthetic gas and one of the most commonly used inhalation anesthetics in experimental and veterinary animal procedures.
There are many different set-ups in laboratories that potentially will expose researchers and employees to isoflurane. Acute exposure with isoflurane includes headaches, dizziness, fatigue, temporary blurring of vision, and nausea. Chronic health effects include a slight increase in risk for miscarriages, liver and kidney disease, and possible reproductive effects. Currently, there is no established exposure limit specific to exposure to isoflurane. The MIT EHS Office is using 2 ppm as an 8-hour time-weighted average (TWA). For additional information about isoflurane safe work practices, please read the Standard Operating Guideline, Isoflurane Safety Guidelines (certificate required).
This document can also be located on the Forms & SOP’s page; search for “Isoflurane Safety Guidelines”.
Additional Resources
The following SOP posters from Stanford University are also available for your review.
- Using EVAC-4 to Scavenge Isoflurane Waste Gas
- Using VetEquip Cube to Scavenge Isoflurane Waste Gas
- Passive Scavenging Using Charcoal Canisters
Lead can be found in many places on campus including paint (certificate login required), solder, ceramic products, and water. Lead and its compounds are toxic and present a health hazard when ingested or inhaled. Once absorbed it is carried throughout the body by the bloodstream to other organs.
Excessive lead levels can result in damage to the brain, kidney, CNS, blood, and reproductive systems. Lead is extremely hazardous to children because it is easily absorbed into their bodies and interferes with the developing brain, central nervous systems, and other organs. Lead is excreted mainly through the urinary and GI tract. Not all the lead is excreted though; some is absorbed in the bones.
MIT is committed to providing students and employees with safe work environments free from any health hazards and we comply with pertinent Federal and State guidelines and regulations. Such regulations require the identification of lead-containing materials, maintaining painted surfaces, effective and proper abatement when necessary, and proper disposal of waste generated by the abatement project.
EHS has developed an FAQ for the MIT Community about lead in drinking water (certificate login required). Please contact EHS, environment@mit.edu or 617-452-3477, if you have questions about lead on campus.
Lithium and sodium compounds include (but are not limited to): butyllithium, lithium aluminum hydride, lithium borohydride, lithium hydride, lithium nitride, sodium aluminum hydride, sodium borohydride, sodium hydride.
The EHS Office strongly recommends the development of a SOP that identifies the appropriate personal protective equipment (PPE), engineering controls, waste management requirements, and emergency response steps to ensure those working with these reactive materials are aware of the hazards.
If your lab plans to, or currently uses, reactive lithium and / or sodium compounds it is recommended that you ensure the appropriate extinguishing agent (such as a Class D extinguisher, sand or a Met-L-X or Lith-X suppression material) are available.
For specific information, refer to Fire Safety. Please note that the list of compounds below is not inclusive. Refer to the Safety Data Sheet (SDS) and/or contact the EHS Office for assistance.
Upon completion of your experiment using lithium or sodium metals or powders, specifically, follow these guidelines or contact the EHS Office for assistance in preparing the waste or surplus materials for hazardous waste pick-up:
- Within the glove box or controlled environment, containerize your waste materials and submerge them in oil.
- Remove the container of waste from the glove box, label it with a red tag, spell out the constituents, indicate Ignitable/Reactive as the associated hazards, date the container, and place it in your lab’s SAA.
- Upon dating, place a waste collection pickup request online for removal from the lab within 3-days.
Mercury is a naturally occurring element that is found in air, water, and soil. It exists in several forms: elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds.
- When elemental mercury is spilled or a device containing mercury breaks, the exposed mercury volatilizes at room temperature and becomes an odorless toxic vapor. Mercury vapors will increase in warm or poorly-ventilated rooms or spaces.
- Mercury and its compounds penetrate the intact skin. Wear nitrile, PVC, or natural rubber gloves for elemental mercury. For organo-alkyl compounds, use Silver Shield or 4H gloves and an outer glove of heavy-duty nitrile or neoprene.
- The nervous system is very sensitive to all forms of mercury. Methylmercury and metallic mercury vapors are more harmful than other forms because more mercury in these forms reaches the brain.
- Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus.
Nanomaterials are defined by the American Society for Testing and Materials as a material with two or three dimensions between 1 to 100 nm. They can be composed of many different base materials such as carbon or silicon, and metals such as gold, cadmium, and selenium. They can also have different shapes: such as nanotubes, nanowires, or crystalline structures such as quantum dots and fullerenes.
Nanomaterials often exhibit very different properties from their respective bulk materials: greater strength, conductivity, and fluorescence, among other properties.
Particles in the nanometer size range do occur both in nature and as an incidental byproduct of existing industrial processes. Nanosized particles are part of the range of atmospheric particles generated by natural events such as volcanic eruptions and forest fires. They also form part of the fumes generated during welding, metal smelting, automobile exhaust, and other industrial processes. One concern about small particles that are less than 10 um is that they are respirable and reach the alveolar spaces of the lungs.
The ability to be taken up by cells is being used to develop nanosized drug delivery systems and does not inherently indicate toxicity.
The toxicity of most nanomaterials is currently unknown. Studies suggest that the levels of toxicity depend on the base material of the nanoparticle, its size and structure, and its substituents and coatings.
The preliminary conclusions to be drawn from the toxicology studies to date is that some types of nanomaterials can be toxic, if they are not bound up in a substrate and they are available to the body. Multiple government organizations are working to fund and assemble toxicology information on these materials. In the interim, MIT researchers must use procedures that prevent inhalation and dermal exposures because at this time nanotoxicology information is limited.
Translocation in the Body
Once in the body, some types of nanoparticles may have the ability to translocate and be distributed to other organs, including the central nervous system. Silver, albumin, and carbon nanoparticles all showed systemic availability after inhalation exposure.
Significant amounts of 13C labeled carbon particles (22-30 nm in diameter) were found in the livers of rats after 6 hours of inhalation exposure to 80 or 180 ug/m3 (Oberdorster et al. 2002). In contrast, only very small amounts of 192Ir particles (15 nm) were found systemically. Oberdorster et al. (2004) also found that inhaled 13 C labeled carbon particles reached the olfactory bulb and also the cerebrum and cerebellum, suggesting that translocation to the brain occurred through the nasal mucosa along the olfactory nerve to the brain.
The ability of nanomaterials to move about the body may depend on their chemical reactivity, surface characteristics, and ability to bind to body proteins.
Handling Nanoparticles
Nanomaterials of uncertain toxicity can be handled using the same precautions currently used at MIT to handle toxic materials: use of exhaust ventilation (such as fume hoods and vented enclosures) to prevent inhalation exposure during procedures that may release aerosols or fibers and use of gloves to prevent dermal exposure. The EHS Office will continue to review health and safety information about nanomaterials as it becomes available and distribute it to the MIT community. The MIT EHS Office considers nanoparticles that have the potential for release into the air to be handled as particularly hazardous substance because their toxicity is, for the most part, unknown and early studies have been suggestive of toxic effects. In the future, many types of nanoparticles may turn out to be of limited toxicity but precaution must be used until we know more.
If you work with nanomaterials in your lab, register your laboratory and your nanomaterials in the Nanomaterial program.
The following best practices should be followed:
- Work with nanoparticles that may release particles should be conducted in enclosures, fume hood, glove boxes, and other vented enclosures.
- All work should be done with gloves (at a minimum disposable nitrile gloves)
- Currently, nanoparticles and solutions containing them are being disposed of as hazardous waste. Label all containers of nanomaterials (including waste) with the designation “nano”.
- develop your laboratory Standard Operating Procedure for nanomaterials work
- Call the EHS Office at 617-452-3477 for exposure evaluation of experimental setups and additional information.
EHS has developed a web course, Nanomaterials Safety and Health (MIT Atlas Learning Center – requires certificates), which includes information on the toxicity of different types of nanomaterials and laboratory practices to prevent exposures.
If you have any questions after reviewing these materials, contact the EHS Office at environment@mit.edu or 617-452-3477. An EHS Officer can also visit your lab for a review of your procedures.
Nanomaterials can be handled in fume hoods, biosafety cabinets, and other exhausted enclosures. However, these hoods often have high air velocities that can be disruptive to handling dry, lightweight nanomaterials.
Laboratories in Mechanical Engineering and Center for Materials Science and Engineering have purchased a specially designed type of enclosure for handling nanopowders. This type of enclosure differs from a traditional fume hood in that the slots for exhausted air are located above the floor of the unit. Therefore air currents do not disturb the handling of light, fluffy nanopowders or nanotubes. These units were originally developed to enclose sensitive balances but can be used either to weigh nanomaterials or manipulate samples.
Contact EHS for vendors who supply these enclosures.
As nanotechnology emerges and evolves, potential environmental applications and human health and environmental implications are under consideration by the EPA and local regulators.
EPA has a number of different offices coordinating its review of this rapidly evolving technology. The EPA is currently trying a voluntary approach to testing and developing a stewardship program. There are currently no guidelines from the EPA specifically addressing the disposal of waste nanomaterials. It seems that regulation at some level is inevitable. Some political subdivisions, including the City of Cambridge, are already evaluating local regulation.
MIT is taking a cautious approach to nano waste management. It is our belief that regulation is inevitable. In order to better understand the potential volumes and characteristics of these waste streams, we are advising that all waste materials potentially contaminated with nanomaterials be identified and evaluated or collected for special waste disposal.
The following waste management guidance applies to nanomaterial-bearing waste streams consisting of:
- Pure nanomaterials (e.g., carbon nanotubes)
- Items contaminated with nanomaterials (e.g., wipes/PPE)
- Liquid suspensions containing nanomaterials
- Solid matrixes with nanomaterials that are friable or have a nanostructure loosely attached to the surface such that they can reasonably be expected to break free or leach out when in contact with air or water, or when subjected to reasonably foreseeable mechanical forces.
The guidance does not apply to nanomaterials embedded in a solid matrix that cannot reasonably be expected to break free or leach out when they contact air or water, but would apply to dusts and fines generated when cutting or milling such materials.
DO NOT put material from nanomaterial – bearing waste streams into the regular trash or down the drain. Before disposal of any waste contaminated with nanomaterial, call the EHS Office (45(617) 452-3477) for a waste determination.
Collect paper, wipes, PPE, and other items with loose contamination in a plastic bag or other sealing container stored in the laboratory hood. When the bag is full, close it, take it out of the hood and place it into a second plastic bag or other sealing container. Label the outer bag with the laboratory’s proper waste label. On the Contents section, note that it contains nano-sized particles and indicate what they are.
Currently, the disposal requirements for the base materials should be considered first when characterizing these materials. If the base material is toxic, such as silver or cadmium, or the carrier is a hazardous waste, such as a flammable solvent or acid, clearly they should carry those identifiers. Many nanoparticles may also be otherwise joined with toxic metals of chemicals. Bulk carbon is considered a flammable solid, so even carbon-based nanomaterials should be collected for determination as hazardous waste characteristics.
- Gradient Corp. Monthly EH&S Nano News
- National Institute for Occupational Safety and Health (NIOSH)
- National Nanotechnology Infrastructure Network (NNIN)
- National Center for Biotechnology Information (NCBI) Pub Med – Search for articles on nanoparticle toxicity
- Safe Nano (UK) – Regularly updated website on health and safety risks of nanotechnology with comments by toxicologists and regulators
Perchloric acid is a clear odorless liquid that is stable at room temperature. It is highly corrosive to all tissues and a strong oxidizer that reacts violently with a wide variety of substances, including organic materials, alcohols, amines, strong acids, strong bases, etc. Contact with wood, paper, and other cellulose products may lead to explosions. Avoid heat as it may form explosive peroxides at elevated temperatures.
Warning: Heated Perchloric Acid can only be used in a fume hood with a functioning water washdown. EHS has one of these hoods and there are others on campus. Contact EHS at 617-452-3477 if you need access to such a hood.
Before working with perchloric acid, review the Standard Operating Procedure.
Decommissioning Fume Hoods: All fume hoods and related ductwork should be checked for explosive perchlorates before dismantling these systems. Call the EHS Office at 617-452-3477 to conduct this test.
General Information
- Peroxide forming chemicals include many common solvents and reagents which are known to form organic peroxides on exposure to air (e.g. tetrahydrofuran, ethers, isopropanol, dioxanes, styrene, 2-hexanol, etc).
- Peroxides are very sensitive to shock, sparks, elevated temperatures, light, strong oxidizing and reducing agents, and friction, such as a cap being twisted open.
- Distillation, evaporation or other concentration of some peroxide-forming chemicals can present a high risk of explosion.
- May be inhibited or uninhibited (this will likely be indicated on the chemical container).
- Inhibition slows, but does not eliminate peroxide formation.
- The Peroxide Forming Chemicals SOP (requires certificate login) provides information and procedures to assure that peroxide forming chemicals are used, stored and disposed safely.
Before Purchase
- Read MIT EHS SOP on Peroxide Forming Chemicals (requires certificate login).
- Determine the Group of the chemical based on the potential of peroxide formation, and its safe storage periods and testing frequency.
- Determine amount you need and check inventory before ordering. Purchase only what you need and always with an inhibitor if available (unless your specific experiment will not tolerate the inhibitor molecule).
- Purchase peroxide test strips as well.
Upon Receiving Chemical
- Check for manufacturer’s expiration date & inhibitor info on the container.
- Label with date received, date opened and assign an expiration date if one is not supplied by the manufacturer. Obtain peroxide forming chemical stickers from the EHS Office.
- Add information to inventory.
- Storage of peroxide forming chemicals in open, partially empty or transparent containers greatly increases the risk of peroxide formation. Store away from light and heat. Protect from light with amber bottles.
- Store in a flammable storage cabinet, a flammable storage refrigerator, or other appropriate location/container.
- Regularly inventory and monitor the container dates and avoid keeping peroxide-forming chemicals longer than the recommended safe storage periods listed in Peroxide Forming Chemicals (requires certificate login).
- Use or dispose of chemical by expiration date.
Testing
- Test containers for peroxides according to the frequency as specified in Peroxide Forming Chemicals (requires certificate login) and before distilling or evaporating peroxide-forming chemicals.
- Peroxide levels must never be allowed to exceed 20 parts-per-million (ppm). Write down the test date and results on the container. You can obtain peroxide former stickers from the EHS Office by completing this form.
- Do not attempt to test if there are possible crystals or particles in bottle or around the cap.
Disposal
- Avoid mixing peroxide-forming hazardous waste with other hazardous wastes.
- Dispose expired or chemical containing peroxides approaching 20 ppm immediately.
- Selected peroxide-forming chemicals may be allowed after safe storage period, subjected to more frequent testing and before each use.
- If > 20 ppm or observed presence of crystals or particles, contact EHS.
Piranha solutions are strong oxidizers used to remove small amounts of organic residues from electronic components. The most commonly used solution at MIT is a 3:1 mixture of sulfuric acid and hydrogen peroxide. The solutions are mixed together just before use and the reaction is extremely exothermic. Solution temperatures quickly rise to greater than 100 degrees C and generate significant quantities of gasses.
Piranha solutions are incompatible with other acids and organic materials such as alcohols and photoresists. The solutions are very corrosive to eyes, skin, and respiratory tract.
There have been multiple incidents in MIT labs where containers have ruptured due to the use of non-venting caps or mixing spent piranha with incompatibles such as isopropanol. In one instance, the glass bottle exploded and scattered glass throughout the lab. Fortunately, there was no one in the lab at the time of the explosion.
Piranha solutions should never be used in airtight containers. Vented caps should always be used and are available at no charge from the EHS Office. Piranha waste should never be mixed with other chemicals.
Before using this material, consult the detailed Chemical Fact Sheet for Piranha Solutions.
Polychlorinated Biphenyl (PCBs) refer to a class of chemicals consisting of 2 aromatic hydrocarbon rings (phenyls), where each hydrogen position on the carbon ring can be substituted with a chlorine atom. As the number of chlorine atoms on the ring increase so does the stability and thermal resistance properties.
- PCBs have joined a class of regulated materials called PBTs: persistent, bio-accumulative, and toxic chemicals
- PCBs do not degrade readily in the environment (persistent)
- PCBs concentrate in the fatty tissues of organisms, and doses are amplified with each step in the food chain (bio-accumulative)
- PCBs can cause chloracne
Although MIT made a concerted effort to dispose of PCB containing items and electrical equipment in the late 1980s, it is possible that an item pre-dating 1980 may surface when a space is cleaned for a lab move or a renovation. If you are unsure of the date of manufacture of any oil-containing equipment, please contact EHS.
For a comprehensive review of pyrophoric and water reactives materials, please review the SOP (certificate required).
Pyrophoric substances are liquids, solids, or gases that will ignite spontaneously in air at or below 130°F. To receive the pyrophoric classification under GHS a chemical must ignite within 5 minutes in air. However, chemicals that ignite after 5 minutes also pose a significant risk to users and should be handled as pyrophoric.
Water-reactive substances are substances that react with water or moisture to release a gas that is either flammable or a health hazard. When water contacts a water-reactive substance, enough heat may be generated to cause spontaneous combustion or an explosion. The guidelines on this page refer to water-reactive substances that have a risk of igniting on contact with moisture, not those that only release toxic gases.
A laboratory specific SOP is required for use of pyrophoric materials. Contact your DLCI’s EHS Coordinator or the EHS Office for assistance.
If your lab plans to, or currently uses, reactive lithium and / or sodium compounds it is recommended that you ensure the appropriate extinguishing agent is available; for example, a Class D extinguisher, sand or a Met-L-X or Lith-X suppression material.
Many factors must be considered when determining what controls are required, including but not limited to the specific pyrophoric chemical(s) being used, type of application, and other hazards. For example, semiconductor research can involve pyrophoric materials that are also highly toxic, requiring additional controls. Contact your EHS Coordinator or the EHS Office for more specific guidance on appropriate controls based on your lab’s research.
Depending on the materials and process, pyrophoric and water-reactive materials should be used in a chemical fume hood (over a spill tray) using techniques that prevent the material from contacting air or in an inert-atmosphere glove box according to the manufacturer’s recommendations.
Before using pyrophoric reagents refer to the Aldrich Technical Bulletins AL-164 and AL-134, which provide detailed instructions on using standard syringe and double-tipped needle transfer techniques to prevent contact with air. Some pyrophoric and water-reactive materials must be handled in a gas-tight syringe to prevent exposure to air.
Flame resistant (FR) lab coats are required when handling pyrophoric substances, including chemicals that release flammable gases that may ignite spontaneously and self-heating chemicals that may catch fire outside of a glove box. FR lab coats should also be worn when working with chemicals that react violently with water or release flammable gas, or when performing potentially vigorous reactions.
Protective eyewear is required when handling pyrophoric and water-reactive materials. Fully enclosed safety goggles or a face shield are preferred, as they offer greater facial protection than safety glasses.
Gloves are required when handling pyrophoric and water-reactive materials. It is recommended that Nomex gloves be worn between two pairs of nitrile gloves for fire protection purposes.
Clothing made from polyester and other synthetic fabrics and loose clothing should not be worn. Always wear long pants and closed toe shoes within the lab. Loose or long hair should be tied back to prevent ignition in the event of a flash fire.
The best way to determine if the substance you are working with is pyrophoric or water reactive is to review the Safety Data Sheet. Safety Data Sheets for all chemicals in a laboratory space must be immediately available. Safety Data Sheets should be updated, reviewed periodically, and used as part of lab specific training.
Common pyrophoric materials include metal hydrides, non metal hydrides, metal halides, alkali metals, metal carbonyls, and metal powders.Note that this list includes examples of pyrophoric and water-reactive materials but is not comprehensive.
Downloadable PDF with hazard details
Many metal powders present special storage and handling concerns when finely divided, including hazards such as air- or water-reactivity or explosive dust generation. Whether a given metal powder exhibits these properties depends on multiple factors, including but not limited to particle size, surface area, moisture level, purity, etc.
Please contact your EHS Coordinator or the EHS Office for assistance when working with small-particle-size metal powders.
Excess pyrophoric chemicals should be treated as hazardous waste. Due to their properties special procedures may be required for waste collection and labs may incur disposal fees based on factors outlined below.
Contact EHS if several bottles are removed from storage at one time, as a fee may be applied depending on the volume. The more toxic and hazardous the chemical and the larger the bottle, the higher the cost tends to be.
Nonreturnable pyrophoric gas cylinders will also incur a cost at the time of disposal. Contact EHS for disposal rates and information on the removal process.
Certain metal powders, such as fine aluminum powder, should be submerged in oil prior to waste collection from the lab. Debris with aluminum powder may be collected with a thin coating of oil and kept separate from other debris waste streams.
Reactive metals, such as lithium, potassium and magnesium, should also be submerged under oil and handled as hazardous waste. Contact EHS for additional guidance.
Tetramethylammonium hydroxide (TMAH) is a particularly hazardous substance. TMAH is commonly used as a developer and an etchant in micro or nanofabrication. TMAH is a solid in the hydrated form or a colorless liquid when dissolved in water and has a strong ammonia-like odor. TMAH is soluble in water, corrosive to metals and tissue and strongly alkali with a pH >13, even at low concentrations. Exposure to TMAH can have negative acute health impacts. TMAH is extremely toxic. As little as, 2% of the body exposed to TMAH can lead to paralysis and death. The TMAH+ cation is a ganglion inhibitor, blocking nerve transmissions. This can lead to cardiac and respiratory failure due to muscle inhibition.
For additional information about TMAH work practices, please read the Chemical Fact Sheet for TMAH.
EHS provides best practices and guidance for safely working with common chemicals/substances, this may also include but not limited to storing, handling and disposing of the chemicals/substances. If you do not see guidance for a particular chemical/substance you are working with or concerned about, please contact EHS, environment@mit.edu or 617-452-3477.
Aqua Regia is a fresh mixture of hydrochloric and nitric acids used to etch metals and clean glassware. It is very corrosive to skin and respiratory tract.
It needs to be mixed fresh for each use and evolves gasses which have caused many accidents and container ruptures. It should be used only when absolutely necessary. For detailed use instructions, you must develop your own standard operating procedure for your process by reviewing the Aqua Regia Chemical Factsheet.
Asbestos is a naturally occurring mineral fiber extensively used in building materials from the 1930s until the 1970s. It is resistant to heat, mechanical stress, and water. Asbestos fibers are only a hazard when they become airborne and can be inhaled.
Learn more about the Asbestos Program
Beryllium metal and its alloys are used in a wide variety of industrial products because they are light and resistant to heat, stress, and strain. Beryllium is highly toxic to the lungs and is a confirmed human carcinogen. All procedures that may be an exposure hazard should be evaluated by the EHS Office to insure that air concentrations are within acceptable levels. The ACGIH TLV for beryllium is 0.05 ug/m3. The OSHA PEL is 0.2 ug/m3.
All employees with potential for exposure can enroll in the annual medical surveillance program sponsored by the MIT Health Department.
For additional information about safe work practices (including use of a respirator, gloves, clothing, etc), consult the MIT Beryllium Program and Procedures.
The inhalation of dust, fumes, or mists containing beryllium or beryllium compounds present a very serious health hazard. Laboratory processes that can produce fumes or inhalable dust include heating, grinding, and machining of beryllium and its alloys.
In humans, beryllium causes both acute and chronic lung disease and lung cancer. Acute beryllium disease has been seen after brief exposures to soluble beryllium compounds. Symptoms range from a mild inflammation of nasal passages to bronchitis and lung inflammation.
Chronic beryllium disease is characterized by lung fibrosis (scarring) and inflammation, causing breathlessness upon exertion, weakness, chest pain, enlarged heart, and ultimately death. Beryllium has been documented to cause lung cancer in industrial beryllium production facilities. Beryllium can also cause allergic skin reactions.
To work safely with beryllium, all labs and shops must do the following:
- All procedures that potentially generate beryllium particulates, such as heating or machining or aerosols of beryllium salts, must be evaluated by the EHS Office to insure that air levels are safe.
- All researchers working with beryllium in a manner that creates airborne exposure can enroll in the Beryllium Surveillance Program at MIT Health by calling (617) 452-3477. The program is voluntary and free.
- Standard operating procedures for specific operations should be established before working with beryllium and its compounds. These will normally include the use of fume hoods or local exhaust ventilation.
- Prior to working with beryllium, employees must receive training from their supervisor. Beryllium users must also complete either Chemical Hygiene or Hazard Communication training and Managing Hazardous Waste training.
The following resources and detailed information is referred to in the Cryogen Safety web course (certificate required).
Best practice for dispensing liquid from a low pressure container to a dewar:
- Don a face shield and safety glasses, cryogenic gloves, long pants without cuffs, closed-toed shoes, and a laboratory coat.
- Next connect a transfer line to the liquid valve, if one is not already present, making sure the fittings match. Please note that the valve will be labeled. The transfer line should have a phase separator attached to reduce turbulence and the release of gas while filling.
- Check the pressure in the cylinder. It should read approximately 22 pounds per square inch. Position the Dewar on the floor at the base of the cylinder, or on some other support below waist level and insert the transfer line into the Dewar. The end of the transfer line should extend to the bottom, or just off the bottom, of the Dewar. Keep bystanders at least four feet away while filling in case of splashing.
- Open the liquid valve one half to three quarters of a turn to begin cooling down the transfer hose and adding the cryogen to the Dewar. The warm hose and Dewar will vaporize the cryogen as it cools and this could create splashing particularly if it is added too quickly. The pressure in the container will drive the liquid out through the valve.
- Once the hose and Dewar have cooled, open the liquid valve to obtain the desired rate of flow. However, if you fully open the valve, be sure to close it a quarter turn. A fully opened valve may freeze in that position causing a spill. A good flow rate is typically evident by a moderate vapor trail coming from the mouth of the Dewar. Listen for the change in sound as the Dewar fills – a higher pitch indicates the Dewar is getting full.
- When full, close the liquid valve. Remove the transfer line but be careful not to drop it or allow the phase separator to hit a solid object which will cause it to break. Watch out for any cryogen that continues to spill out of the transfer hose. Finally, place the top on the Dewar, pushing it all the way on and then pulling it up so that it is loose.
Best practice for dispensing gas from a high pressure container to equipment or system:
- Don cryogenic gloves, safety glasses, long pants without cuffs, closed-toed shoes, and a laboratory coat.
- Check the pressure in the cylinder. It should be approximately 230 pounds per square inch, but this will vary with the gas dispensed.
- Next connect the inlet of a suitable regulator to the gas use valve or a transfer line from this valve to an appropriate wall mounted regulator. Please note that the gas withdrawal valve will be labeled. The regulator should be designed for use with cryogens and adjustable over the desired pressure range.
- The outlet of the regulator is connected to the system receiving the gas using the appropriate transfer line – in this case it’s a dedicated gas line.
- Next close the regulator valve and open the gas use valve. Adjust the gas regulator to deliver the gas at the desired pressure, for example, 90 pounds per square inch. At this point you may begin withdrawing gas.
- In applications where large volumes of gas will be withdrawn from the container, the pressure building valve will be opened. This valve operates an internal circuit that allows more liquid to vaporize then would naturally occur through evaporation alone. The vendor supplying the container generally knows your application and opens or closes this valve when delivered.
The transportation of cryogenic containers in elevators represents a potential asphyxiation risk if researchers become trapped in an elevator with a container of cryogen. If a passenger elevator must be used, the first person rolls the container into the elevator, posts a clearly visible sign that warns staff and students not to enter the elevator. The first person pushes the elevator button for the appropriate floor and immediately gets off the elevator. The second person meets the elevator, removes the container and the sign.
This table lists the change in volume as the gas transitions from liquid to gas at room temperature. The resulting pressure that would be generated inside a container from trapped liquid under these conditions is also listed.
Helium | Nitrogen | Oxygen | CO2 | |
---|---|---|---|---|
Boiling point °F (1 @atm) | -452 | -321 | -297 | -108 |
Change in volume as liquid expands to gas at room temperature (liquid-to-gas expansion ratio) | 780 | 710 | 875 | 790 |
Pressure generated from trapped liquid allowed to warm to room temperature | 10,950 psig | 10,230 psig | Not Specified | Not Specified |
Note 1: Although CO2, which has a slightly higher boiling is technically not cryogenic liquid but has similar properties and is often included in this category. (Note: Source Argonne National Laboratory)
Resources / Additional Information
- LN2 Ice Cream Safety Plan Template
- Cryogenic Liquids SOP (certificate required)
- Cryogen Valve Diagrams
- Cryogen Safety Web Course Narrative
- Safetygram – Helium
- Safetygram – Oxygen
Cyanide salts (sodium and potassium) have a white crystalline or powder appearance. They are highly toxic by inhalation, ingestion, and can even be absorbed through the skin. As little as 50 mg can be fatal to a human being. Mixing dry salts with atmospheric moisture or with acids can release poisonous hydrogen cyanide gas which can be fatal.
MIT Procurement will not allow you to purchase cyanide salts unless the EHS Office approves your order. You must review and follow all the Cyanide Salts Safety Guidelines.
Formaldehyde is classified by OSHA as a Particularly Hazardous Substance, a probable carcinogen, and a respiratory and skin sensitizer. It has a strong odor detectable at 0.04 to 1 parts per million (ppm). The OSHA 8 hour Permissible Exposure Limit is 0.75 ppm. The 15 minute Short Term Exposure Limit is 2 ppm.
Formaldehyde can be used safely provided that the following precautions are followed:
- Use in a fume hood or other ventilated enclosure such as a dissection hood or ventilated downdraft table unless very dilute or small quantities.
- Wear gloves with good resistance to formaldehyde, such as the disposable nitrile Best NDex glove – Latex gloves provide short term splash resistance only and should generally not be worn for formaldehyde work.
- All formaldehyde waste should be collected and disposed of as hazardous waste.
- The Chemical Hygiene Lab Specific Training for your lab should cover formaldehyde hazards and safe use practices.
- Call the EHS Office (617-452-3477) if you can smell formaldehyde during your procedures.
- Make an appointment with the MIT Health Department (617-253-4481) if you experience any symptoms of eye, nose, or throat irritation during your work with formaldehyde.
MIT must identify all laboratory activities that are above the OSHA action level or short term exposure level (STEL) through initial air monitoring and provide training, medical surveillance, and engineering and work practice controls if air levels warrant it. The Industrial Hygiene Program (IHP) in the EHS Office has performed extensive air sampling for formaldehyde during a variety of lab activities such as animal perfusion, dissections, and tissue fixation and found the results to be below OSHA levels provided that suitable exhaust ventilation is used.
With proper exhaust ventilation, you should not detect any odors from formaldehyde work nor experience any symptoms of exposure such as eye tearing or throat irritation. If you do, please contact EHS immediately at (617) 452-3477 for an evaluation.
EHS sends a questionnaire annually to laboratory EHS Representatives to survey formaldehyde use and conducts air sampling of procedures where there may be a potential for exposure. Notify EHS for an evaluation if your procedures change and you work with large quantities of formaldehyde, perform animal perfusions, or do extensive tissue dissection work.
Hydrofluoric acid (HF) is a particularly hazardous substance, like many acids, but has added dangers that make it especially dangerous. It is less dissociated than most acids and deeply penetrates the skin. Symptoms of exposure may be delayed for up to 24 hours, even with dilute solutions. HF burns affect deep tissue layers, are extremely painful and disfiguring. The highly reactive fluoride ion circulates throughout the body and can cause multiple organ toxicity, including heart arrhythmias and death, if not treated.
Any suspected exposure to HF should be immediately flooded with water, decontaminated with calcium gluconate gel, and receive medical attention immediately. To do so, call 100 from a MIT phone or 617-253-1212 from a cell phone. An alternative response for an exposure may be indicated in a written SOP only after consultation with EHS and MIT Health.
All laboratories using HF must have unexpired calcium gluconate decontamination gel on hand. You may obtain it from the EHS Office by completing this form.
Calcium Gluconate Gel Request Form
All personnel are required to be trained by the EHS Office before beginning work with HF. The training covers safe use, personal protective equipment, and decontamination procedures.
To register or complete the training via the web, visit MIT Atlas (certificate login required) and follow these steps:
- Search for and select the Learning Center.
- Under the My Profile tab, click the “Create EHS Profile” or “Update PI / Activities” button.
- Select “Save and Continue.”
- On the Select Your Activities page, scroll down to the Chemical Safety section. Check the box for “Use or work in the area that store or uses hydrofluoric acid.”
- Click the “Submit” button at the bottom of the page.
- Options for completing the training will appear under the My Training Needs tab. This training can be completed via a classroom training or web course.
Isoflurane is an anesthetic gas that is widely used at MIT. Isoflurane is a halogenated anesthetic gas and one of the most commonly used inhalation anesthetics in experimental and veterinary animal procedures.
There are many different set-ups in laboratories that potentially will expose researchers and employees to isoflurane. Acute exposure with isoflurane includes headaches, dizziness, fatigue, temporary blurring of vision, and nausea. Chronic health effects include a slight increase in risk for miscarriages, liver and kidney disease, and possible reproductive effects. Currently, there is no established exposure limit specific to exposure to isoflurane. The MIT EHS Office is using 2 ppm as an 8-hour time-weighted average (TWA). For additional information about isoflurane safe work practices, please read the Standard Operating Guideline, Isoflurane Safety Guidelines (certificate required).
This document can also be located on the Forms & SOP’s page; search for “Isoflurane Safety Guidelines”.
Additional Resources
The following SOP posters from Stanford University are also available for your review.
- Using EVAC-4 to Scavenge Isoflurane Waste Gas
- Using VetEquip Cube to Scavenge Isoflurane Waste Gas
- Passive Scavenging Using Charcoal Canisters
Lead can be found in many places on campus including paint (certificate login required), solder, ceramic products, and water. Lead and its compounds are toxic and present a health hazard when ingested or inhaled. Once absorbed it is carried throughout the body by the bloodstream to other organs.
Excessive lead levels can result in damage to the brain, kidney, CNS, blood, and reproductive systems. Lead is extremely hazardous to children because it is easily absorbed into their bodies and interferes with the developing brain, central nervous systems, and other organs. Lead is excreted mainly through the urinary and GI tract. Not all the lead is excreted though; some is absorbed in the bones.
MIT is committed to providing students and employees with safe work environments free from any health hazards and we comply with pertinent Federal and State guidelines and regulations. Such regulations require the identification of lead-containing materials, maintaining painted surfaces, effective and proper abatement when necessary, and proper disposal of waste generated by the abatement project.
EHS has developed an FAQ for the MIT Community about lead in drinking water (certificate login required). Please contact EHS, environment@mit.edu or 617-452-3477, if you have questions about lead on campus.
Lithium and sodium compounds include (but are not limited to): butyllithium, lithium aluminum hydride, lithium borohydride, lithium hydride, lithium nitride, sodium aluminum hydride, sodium borohydride, sodium hydride.
The EHS Office strongly recommends the development of a SOP that identifies the appropriate personal protective equipment (PPE), engineering controls, waste management requirements, and emergency response steps to ensure those working with these reactive materials are aware of the hazards.
If your lab plans to, or currently uses, reactive lithium and / or sodium compounds it is recommended that you ensure the appropriate extinguishing agent (such as a Class D extinguisher, sand or a Met-L-X or Lith-X suppression material) are available.
For specific information, refer to Fire Safety. Please note that the list of compounds below is not inclusive. Refer to the Safety Data Sheet (SDS) and/or contact the EHS Office for assistance.
Upon completion of your experiment using lithium or sodium metals or powders, specifically, follow these guidelines or contact the EHS Office for assistance in preparing the waste or surplus materials for hazardous waste pick-up:
- Within the glove box or controlled environment, containerize your waste materials and submerge them in oil.
- Remove the container of waste from the glove box, label it with a red tag, spell out the constituents, indicate Ignitable/Reactive as the associated hazards, date the container, and place it in your lab’s SAA.
- Upon dating, place a waste collection pickup request online for removal from the lab within 3-days.
Mercury is a naturally occurring element that is found in air, water, and soil. It exists in several forms: elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds.
- When elemental mercury is spilled or a device containing mercury breaks, the exposed mercury volatilizes at room temperature and becomes an odorless toxic vapor. Mercury vapors will increase in warm or poorly-ventilated rooms or spaces.
- Mercury and its compounds penetrate the intact skin. Wear nitrile, PVC, or natural rubber gloves for elemental mercury. For organo-alkyl compounds, use Silver Shield or 4H gloves and an outer glove of heavy-duty nitrile or neoprene.
- The nervous system is very sensitive to all forms of mercury. Methylmercury and metallic mercury vapors are more harmful than other forms because more mercury in these forms reaches the brain.
- Exposure to high levels of metallic, inorganic, or organic mercury can permanently damage the brain, kidneys, and developing fetus.
Nanomaterials are defined by the American Society for Testing and Materials as a material with two or three dimensions between 1 to 100 nm. They can be composed of many different base materials such as carbon or silicon, and metals such as gold, cadmium, and selenium. They can also have different shapes: such as nanotubes, nanowires, or crystalline structures such as quantum dots and fullerenes.
Nanomaterials often exhibit very different properties from their respective bulk materials: greater strength, conductivity, and fluorescence, among other properties.
Particles in the nanometer size range do occur both in nature and as an incidental byproduct of existing industrial processes. Nanosized particles are part of the range of atmospheric particles generated by natural events such as volcanic eruptions and forest fires. They also form part of the fumes generated during welding, metal smelting, automobile exhaust, and other industrial processes. One concern about small particles that are less than 10 um is that they are respirable and reach the alveolar spaces of the lungs.
The ability to be taken up by cells is being used to develop nanosized drug delivery systems and does not inherently indicate toxicity.
The toxicity of most nanomaterials is currently unknown. Studies suggest that the levels of toxicity depend on the base material of the nanoparticle, its size and structure, and its substituents and coatings.
The preliminary conclusions to be drawn from the toxicology studies to date is that some types of nanomaterials can be toxic, if they are not bound up in a substrate and they are available to the body. Multiple government organizations are working to fund and assemble toxicology information on these materials. In the interim, MIT researchers must use procedures that prevent inhalation and dermal exposures because at this time nanotoxicology information is limited.
Translocation in the Body
Once in the body, some types of nanoparticles may have the ability to translocate and be distributed to other organs, including the central nervous system. Silver, albumin, and carbon nanoparticles all showed systemic availability after inhalation exposure.
Significant amounts of 13C labeled carbon particles (22-30 nm in diameter) were found in the livers of rats after 6 hours of inhalation exposure to 80 or 180 ug/m3 (Oberdorster et al. 2002). In contrast, only very small amounts of 192Ir particles (15 nm) were found systemically. Oberdorster et al. (2004) also found that inhaled 13 C labeled carbon particles reached the olfactory bulb and also the cerebrum and cerebellum, suggesting that translocation to the brain occurred through the nasal mucosa along the olfactory nerve to the brain.
The ability of nanomaterials to move about the body may depend on their chemical reactivity, surface characteristics, and ability to bind to body proteins.
Handling Nanoparticles
Nanomaterials of uncertain toxicity can be handled using the same precautions currently used at MIT to handle toxic materials: use of exhaust ventilation (such as fume hoods and vented enclosures) to prevent inhalation exposure during procedures that may release aerosols or fibers and use of gloves to prevent dermal exposure. The EHS Office will continue to review health and safety information about nanomaterials as it becomes available and distribute it to the MIT community. The MIT EHS Office considers nanoparticles that have the potential for release into the air to be handled as particularly hazardous substance because their toxicity is, for the most part, unknown and early studies have been suggestive of toxic effects. In the future, many types of nanoparticles may turn out to be of limited toxicity but precaution must be used until we know more.
If you work with nanomaterials in your lab, register your laboratory and your nanomaterials in the Nanomaterial program.
The following best practices should be followed:
- Work with nanoparticles that may release particles should be conducted in enclosures, fume hood, glove boxes, and other vented enclosures.
- All work should be done with gloves (at a minimum disposable nitrile gloves)
- Currently, nanoparticles and solutions containing them are being disposed of as hazardous waste. Label all containers of nanomaterials (including waste) with the designation “nano”.
- develop your laboratory Standard Operating Procedure for nanomaterials work
- Call the EHS Office at 617-452-3477 for exposure evaluation of experimental setups and additional information.
EHS has developed a web course, Nanomaterials Safety and Health (MIT Atlas Learning Center – requires certificates), which includes information on the toxicity of different types of nanomaterials and laboratory practices to prevent exposures.
If you have any questions after reviewing these materials, contact the EHS Office at environment@mit.edu or 617-452-3477. An EHS Officer can also visit your lab for a review of your procedures.
Nanomaterials can be handled in fume hoods, biosafety cabinets, and other exhausted enclosures. However, these hoods often have high air velocities that can be disruptive to handling dry, lightweight nanomaterials.
Laboratories in Mechanical Engineering and Center for Materials Science and Engineering have purchased a specially designed type of enclosure for handling nanopowders. This type of enclosure differs from a traditional fume hood in that the slots for exhausted air are located above the floor of the unit. Therefore air currents do not disturb the handling of light, fluffy nanopowders or nanotubes. These units were originally developed to enclose sensitive balances but can be used either to weigh nanomaterials or manipulate samples.
Contact EHS for vendors who supply these enclosures.
As nanotechnology emerges and evolves, potential environmental applications and human health and environmental implications are under consideration by the EPA and local regulators.
EPA has a number of different offices coordinating its review of this rapidly evolving technology. The EPA is currently trying a voluntary approach to testing and developing a stewardship program. There are currently no guidelines from the EPA specifically addressing the disposal of waste nanomaterials. It seems that regulation at some level is inevitable. Some political subdivisions, including the City of Cambridge, are already evaluating local regulation.
MIT is taking a cautious approach to nano waste management. It is our belief that regulation is inevitable. In order to better understand the potential volumes and characteristics of these waste streams, we are advising that all waste materials potentially contaminated with nanomaterials be identified and evaluated or collected for special waste disposal.
The following waste management guidance applies to nanomaterial-bearing waste streams consisting of:
- Pure nanomaterials (e.g., carbon nanotubes)
- Items contaminated with nanomaterials (e.g., wipes/PPE)
- Liquid suspensions containing nanomaterials
- Solid matrixes with nanomaterials that are friable or have a nanostructure loosely attached to the surface such that they can reasonably be expected to break free or leach out when in contact with air or water, or when subjected to reasonably foreseeable mechanical forces.
The guidance does not apply to nanomaterials embedded in a solid matrix that cannot reasonably be expected to break free or leach out when they contact air or water, but would apply to dusts and fines generated when cutting or milling such materials.
DO NOT put material from nanomaterial – bearing waste streams into the regular trash or down the drain. Before disposal of any waste contaminated with nanomaterial, call the EHS Office (45(617) 452-3477) for a waste determination.
Collect paper, wipes, PPE, and other items with loose contamination in a plastic bag or other sealing container stored in the laboratory hood. When the bag is full, close it, take it out of the hood and place it into a second plastic bag or other sealing container. Label the outer bag with the laboratory’s proper waste label. On the Contents section, note that it contains nano-sized particles and indicate what they are.
Currently, the disposal requirements for the base materials should be considered first when characterizing these materials. If the base material is toxic, such as silver or cadmium, or the carrier is a hazardous waste, such as a flammable solvent or acid, clearly they should carry those identifiers. Many nanoparticles may also be otherwise joined with toxic metals of chemicals. Bulk carbon is considered a flammable solid, so even carbon-based nanomaterials should be collected for determination as hazardous waste characteristics.
- Gradient Corp. Monthly EH&S Nano News
- National Institute for Occupational Safety and Health (NIOSH)
- National Nanotechnology Infrastructure Network (NNIN)
- National Center for Biotechnology Information (NCBI) Pub Med – Search for articles on nanoparticle toxicity
- Safe Nano (UK) – Regularly updated website on health and safety risks of nanotechnology with comments by toxicologists and regulators
Perchloric acid is a clear odorless liquid that is stable at room temperature. It is highly corrosive to all tissues and a strong oxidizer that reacts violently with a wide variety of substances, including organic materials, alcohols, amines, strong acids, strong bases, etc. Contact with wood, paper, and other cellulose products may lead to explosions. Avoid heat as it may form explosive peroxides at elevated temperatures.
Warning: Heated Perchloric Acid can only be used in a fume hood with a functioning water washdown. EHS has one of these hoods and there are others on campus. Contact EHS at 617-452-3477 if you need access to such a hood.
Before working with perchloric acid, review the Standard Operating Procedure.
Decommissioning Fume Hoods: All fume hoods and related ductwork should be checked for explosive perchlorates before dismantling these systems. Call the EHS Office at 617-452-3477 to conduct this test.
General Information
- Peroxide forming chemicals include many common solvents and reagents which are known to form organic peroxides on exposure to air (e.g. tetrahydrofuran, ethers, isopropanol, dioxanes, styrene, 2-hexanol, etc).
- Peroxides are very sensitive to shock, sparks, elevated temperatures, light, strong oxidizing and reducing agents, and friction, such as a cap being twisted open.
- Distillation, evaporation or other concentration of some peroxide-forming chemicals can present a high risk of explosion.
- May be inhibited or uninhibited (this will likely be indicated on the chemical container).
- Inhibition slows, but does not eliminate peroxide formation.
- The Peroxide Forming Chemicals SOP (requires certificate login) provides information and procedures to assure that peroxide forming chemicals are used, stored and disposed safely.
Before Purchase
- Read MIT EHS SOP on Peroxide Forming Chemicals (requires certificate login).
- Determine the Group of the chemical based on the potential of peroxide formation, and its safe storage periods and testing frequency.
- Determine amount you need and check inventory before ordering. Purchase only what you need and always with an inhibitor if available (unless your specific experiment will not tolerate the inhibitor molecule).
- Purchase peroxide test strips as well.
Upon Receiving Chemical
- Check for manufacturer’s expiration date & inhibitor info on the container.
- Label with date received, date opened and assign an expiration date if one is not supplied by the manufacturer. Obtain peroxide forming chemical stickers from the EHS Office.
- Add information to inventory.
- Storage of peroxide forming chemicals in open, partially empty or transparent containers greatly increases the risk of peroxide formation. Store away from light and heat. Protect from light with amber bottles.
- Store in a flammable storage cabinet, a flammable storage refrigerator, or other appropriate location/container.
- Regularly inventory and monitor the container dates and avoid keeping peroxide-forming chemicals longer than the recommended safe storage periods listed in Peroxide Forming Chemicals (requires certificate login).
- Use or dispose of chemical by expiration date.
Testing
- Test containers for peroxides according to the frequency as specified in Peroxide Forming Chemicals (requires certificate login) and before distilling or evaporating peroxide-forming chemicals.
- Peroxide levels must never be allowed to exceed 20 parts-per-million (ppm). Write down the test date and results on the container. You can obtain peroxide former stickers from the EHS Office by completing this form.
- Do not attempt to test if there are possible crystals or particles in bottle or around the cap.
Disposal
- Avoid mixing peroxide-forming hazardous waste with other hazardous wastes.
- Dispose expired or chemical containing peroxides approaching 20 ppm immediately.
- Selected peroxide-forming chemicals may be allowed after safe storage period, subjected to more frequent testing and before each use.
- If > 20 ppm or observed presence of crystals or particles, contact EHS.
Piranha solutions are strong oxidizers used to remove small amounts of organic residues from electronic components. The most commonly used solution at MIT is a 3:1 mixture of sulfuric acid and hydrogen peroxide. The solutions are mixed together just before use and the reaction is extremely exothermic. Solution temperatures quickly rise to greater than 100 degrees C and generate significant quantities of gasses.
Piranha solutions are incompatible with other acids and organic materials such as alcohols and photoresists. The solutions are very corrosive to eyes, skin, and respiratory tract.
There have been multiple incidents in MIT labs where containers have ruptured due to the use of non-venting caps or mixing spent piranha with incompatibles such as isopropanol. In one instance, the glass bottle exploded and scattered glass throughout the lab. Fortunately, there was no one in the lab at the time of the explosion.
Piranha solutions should never be used in airtight containers. Vented caps should always be used and are available at no charge from the EHS Office. Piranha waste should never be mixed with other chemicals.
Before using this material, consult the detailed Chemical Fact Sheet for Piranha Solutions.
Polychlorinated Biphenyl (PCBs) refer to a class of chemicals consisting of 2 aromatic hydrocarbon rings (phenyls), where each hydrogen position on the carbon ring can be substituted with a chlorine atom. As the number of chlorine atoms on the ring increase so does the stability and thermal resistance properties.
- PCBs have joined a class of regulated materials called PBTs: persistent, bio-accumulative, and toxic chemicals
- PCBs do not degrade readily in the environment (persistent)
- PCBs concentrate in the fatty tissues of organisms, and doses are amplified with each step in the food chain (bio-accumulative)
- PCBs can cause chloracne
Although MIT made a concerted effort to dispose of PCB containing items and electrical equipment in the late 1980s, it is possible that an item pre-dating 1980 may surface when a space is cleaned for a lab move or a renovation. If you are unsure of the date of manufacture of any oil-containing equipment, please contact EHS.
For a comprehensive review of pyrophoric and water reactives materials, please review the SOP (certificate required).
Pyrophoric substances are liquids, solids, or gases that will ignite spontaneously in air at or below 130°F. To receive the pyrophoric classification under GHS a chemical must ignite within 5 minutes in air. However, chemicals that ignite after 5 minutes also pose a significant risk to users and should be handled as pyrophoric.
Water-reactive substances are substances that react with water or moisture to release a gas that is either flammable or a health hazard. When water contacts a water-reactive substance, enough heat may be generated to cause spontaneous combustion or an explosion. The guidelines on this page refer to water-reactive substances that have a risk of igniting on contact with moisture, not those that only release toxic gases.
A laboratory specific SOP is required for use of pyrophoric materials. Contact your DLCI’s EHS Coordinator or the EHS Office for assistance.
If your lab plans to, or currently uses, reactive lithium and / or sodium compounds it is recommended that you ensure the appropriate extinguishing agent is available; for example, a Class D extinguisher, sand or a Met-L-X or Lith-X suppression material.
Many factors must be considered when determining what controls are required, including but not limited to the specific pyrophoric chemical(s) being used, type of application, and other hazards. For example, semiconductor research can involve pyrophoric materials that are also highly toxic, requiring additional controls. Contact your EHS Coordinator or the EHS Office for more specific guidance on appropriate controls based on your lab’s research.
Depending on the materials and process, pyrophoric and water-reactive materials should be used in a chemical fume hood (over a spill tray) using techniques that prevent the material from contacting air or in an inert-atmosphere glove box according to the manufacturer’s recommendations.
Before using pyrophoric reagents refer to the Aldrich Technical Bulletins AL-164 and AL-134, which provide detailed instructions on using standard syringe and double-tipped needle transfer techniques to prevent contact with air. Some pyrophoric and water-reactive materials must be handled in a gas-tight syringe to prevent exposure to air.
Flame resistant (FR) lab coats are required when handling pyrophoric substances, including chemicals that release flammable gases that may ignite spontaneously and self-heating chemicals that may catch fire outside of a glove box. FR lab coats should also be worn when working with chemicals that react violently with water or release flammable gas, or when performing potentially vigorous reactions.
Protective eyewear is required when handling pyrophoric and water-reactive materials. Fully enclosed safety goggles or a face shield are preferred, as they offer greater facial protection than safety glasses.
Gloves are required when handling pyrophoric and water-reactive materials. It is recommended that Nomex gloves be worn between two pairs of nitrile gloves for fire protection purposes.
Clothing made from polyester and other synthetic fabrics and loose clothing should not be worn. Always wear long pants and closed toe shoes within the lab. Loose or long hair should be tied back to prevent ignition in the event of a flash fire.
The best way to determine if the substance you are working with is pyrophoric or water reactive is to review the Safety Data Sheet. Safety Data Sheets for all chemicals in a laboratory space must be immediately available. Safety Data Sheets should be updated, reviewed periodically, and used as part of lab specific training.
Common pyrophoric materials include metal hydrides, non metal hydrides, metal halides, alkali metals, metal carbonyls, and metal powders.Note that this list includes examples of pyrophoric and water-reactive materials but is not comprehensive.
Downloadable PDF with hazard details
Many metal powders present special storage and handling concerns when finely divided, including hazards such as air- or water-reactivity or explosive dust generation. Whether a given metal powder exhibits these properties depends on multiple factors, including but not limited to particle size, surface area, moisture level, purity, etc.
Please contact your EHS Coordinator or the EHS Office for assistance when working with small-particle-size metal powders.
Excess pyrophoric chemicals should be treated as hazardous waste. Due to their properties special procedures may be required for waste collection and labs may incur disposal fees based on factors outlined below.
Contact EHS if several bottles are removed from storage at one time, as a fee may be applied depending on the volume. The more toxic and hazardous the chemical and the larger the bottle, the higher the cost tends to be.
Nonreturnable pyrophoric gas cylinders will also incur a cost at the time of disposal. Contact EHS for disposal rates and information on the removal process.
Certain metal powders, such as fine aluminum powder, should be submerged in oil prior to waste collection from the lab. Debris with aluminum powder may be collected with a thin coating of oil and kept separate from other debris waste streams.
Reactive metals, such as lithium, potassium and magnesium, should also be submerged under oil and handled as hazardous waste. Contact EHS for additional guidance.
Tetramethylammonium hydroxide (TMAH) is a particularly hazardous substance. TMAH is commonly used as a developer and an etchant in micro or nanofabrication. TMAH is a solid in the hydrated form or a colorless liquid when dissolved in water and has a strong ammonia-like odor. TMAH is soluble in water, corrosive to metals and tissue and strongly alkali with a pH >13, even at low concentrations. Exposure to TMAH can have negative acute health impacts. TMAH is extremely toxic. As little as, 2% of the body exposed to TMAH can lead to paralysis and death. The TMAH+ cation is a ganglion inhibitor, blocking nerve transmissions. This can lead to cardiac and respiratory failure due to muscle inhibition.
For additional information about TMAH work practices, please read the Chemical Fact Sheet for TMAH.