Lab staff routinely encounter a variety of physical hazards during daily work. As with chemical risks, awareness, careful planning, proper use of personal protective equipment (PPE), and adherence to basic safety protocols are key to preventing accidents involving physical hazards.

It is the responsibility of the Principal Investigator and laboratory supervisor to ensure that staff and students in their laboratories receive adequate training and information specific to the physical hazards in their work environment.

Autoclaves

Autoclaves pose several potential hazards including:

• Heat, steam, and pressure
• Thermal burns from steam and hot liquids
• Cuts from exploding glass

General Autoclave Safety Guidelines

• All users receive proper training before operating an autoclave.  Read the owner’s manual and post operating instructions near the unit.
• Follow the manufacturer’s guidelines for loading. Always close and latch the autoclave door securely.
• Use secondary containment trays when autoclaving liquids. Add a small amount of water to the tray to ensure even heating and reduce the risk of cracking or spillage.
• Fill bottles of liquid only halfway and loosen caps on bottles and tubes to prevent breakage from expansion.
• Do not overload the autoclave. Leave space between items to allow steam circulation.
• Be aware that liquids, especially in large quantities, can be superheated. Jarring them may cause sudden boiling over and result in burns.
• At the end of a cycle, open the door slowly. Crack it first to allow steam to escape gradually, then open fully after several minutes. Opening the door suddenly can scald a bare hand, arm, or face.
• Wait at least five minutes after opening the door before removing items.
• Do not carry hot glassware or large liquid containers by hand. Use a cart to transport items safely.
• Always wear appropriate PPE, including eye protection, heat-resistant insulated gloves, and lab coat or apron.

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Battery Charging

Lead acid batteries contain corrosive liquids and generate hydrogen gas during charging which poses an explosion hazard. The following guidelines should be followed for battery charging areas:

• A “No smoking” sign should be posted.
• Before working, remove all jewelry from hands and arms and any dangling jewelry to prevent accidental contact with battery connections. This can cause sparks that can ignite vapors.
• Always wear appropriate PPE such as rubber or synthetic aprons, splash goggles (ideally in combination with a face shield), and thick Neoprene, Viton, or Butyl gloves.
• A plumbed emergency eyewash station must be readily available near the station. Hand held eyewash bottles do not meet this criterion.
• A class B rated fire extinguisher needs to be readily available. If none is available, contact the University Fire Marshal Group.
• Ensure there is adequate ventilation available to prevent the buildup of potentially flammable and explosive gases.
• Keep all ignition sources away from the area.
• Stand clear of batteries while charging.
• Keep vent caps tight and level.
• Only use the appropriate equipment for charging.
• Store unused batteries in secondary containment to prevent spills.
• Have an acid spill kit available. The waste from a spill may contain lead and neutralized wastes may be toxic. Contact EHS for hazardous waste disposal.
• Properly dispose of your used batteries.

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Centrifuges

General Centrifuge Safety Guidelines

• Read and follow the manufacturer's instructions. Keep the operating manual accessible near the unit. Contact the manufacturer for a replacement if needed.
• Handle, load, clean, and inspect rotors according to the manufacturer's recommendations.
• Balance samples precisely. Balancing tolerances vary by rotor type and speed. Improper balancing can cause severe equipment damage.
• Check the condition of all tubes and bottles. Ensure the rotor and lid are securely fastened.
• Maintain a logbook of rotor use for each rotor, recording the speed and length of time for each use.
• Be aware that many rotors may be "de-rated." To avoid catastrophic rotor failure, many types of rotors must be operated at a reduced speed after being used a certain number of hours and eventually taken out of service and discarded.
• Use only rotors approved for the specific centrifuge model.
• Keep the centrifuge in good working condition. Do not operate a unit with broken latches or other mechanical issues.
• When centrifuging biohazardous materials, always load and unload the centrifuge rotor in a biosafety cabinet.

Centrifuge Rotor Care

Proper care extends the life of centrifuge rotors and ensures safety.

• Keeping the rotor clean and dry to prevent corrosion.
• Remove adapters after use and inspect for damage or wear.
• Store rotors upside down in a warm, dry place to minimize condensation.

Follow manufacturer recommendations for:

• Routine cleaning
• Regular inspections
• Regular polishing
• Lubricating O-rings
• Decontamination after exposure to radioactive or biological materials

Any rotor that has been dropped or shows any sign of damage must be immediately removed from service and inspected by the manufacturer’ or an authorized representative.

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Cold Traps

Cold traps can collect hazardous substances. Proper handling procedures and PPE are essential. Hazards associated with cold traps include flammability, toxicity, and cryogenic temperatures, which can burn the skin.

When using liquid nitrogen, always evacuate the chamber before adding coolant. This prevents the condensation of oxygen from the air, which has a higher boiling point than nitrogen. Since oxygen in air has a higher boiling point than nitrogen, liquid nitrogen can be produced and cause an explosion hazard, both from rapid expansion of condensed gas and from exothermic oxidation of organic material upon thawing.

Boiling and splashing generally occur when charging (cooling) a warm container. Stand clear and wear appropriate PPE, and add liquids slowly and in small amounts to minimize splash risk. A blue tint in liquid nitrogen indicates liquid oxygen contamination which presents an explosion hazard. Contaminated liquid nitrogen should be disposed of properly. Contact EHS for guidance at 541-346-3192. 

If cold traps are used under vacuum, refer to the Glass Under Vacuum section for additional safety guidelines. 

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Cryogenic Safety

Cryogenic gases are materials that exist as gases at standard temperature and pressure but are liquified or solidified at extremely low temperatures. Commonly used cryogenic materials include the liquids nitrogen, argon, and helium, and solid carbon dioxide (dry ice).

Hazards

Hazards associated with direct personal exposure to cryogenic fluids include:

Frostbite 

Liquid and solid cryogenics can cause severe cold contact burns by the liquid, and frostbite or cold exposure by the vapor. Dispensing areas need to be well ventilated. Avoid storing cryogenics in cold rooms, environmental chambers, and other areas with poor ventilation. Always wear appropriate PPE when handling.

Asphyxiation 

The ability of the liquid to rapidly convert to large quantities of gas associated with evaporation of cryogenic liquid spills can result in asphyxiation. 

For instance, nitrogen expands approximately 700 times in volume going from liquid to gas at ambient temperature. Total displacement of oxygen by another gas, such as carbon dioxide, will result in unconsciousness, followed by death. Exposure to oxygen-deficient atmospheres may produce dizziness, nausea, vomiting, loss of consciousness, and death. Such symptoms may occur in seconds without warning. Death may result from errors in judgment, confusion, or loss of consciousness that prevents self-rescue. 

Working with cryogenic substances in confined spaces, such as walk-in coolers, can be especially hazardous. Where cryogenic materials are used, a hazard assessment is required to determine the potential for an oxygen-deficient condition. Controls such as ventilation and/or gas detection systems may be required to safeguard individuals. If necessary, install an oxygen monitor/oxygen deficiency alarm and/or toxic gas monitor before working these materials in confined areas. Asphyxiation and chemical toxicity are hazards encountered when entering an area that has been used to store cryogenic liquids if proper ventilation/purging techniques are not employed.

Toxicity 

Although many commonly used cryogenic gases are inert, some (e.g. carbon monoxide, fluorine) are toxic. Always consult the Safety Data Sheets for specific hazards.  Such gas cylinders should be stored in a well-ventilated area in case of accidental discharge.

Flammability and Explosion Hazards 

Fire or explosion may result from the evaporation and vapor buildup of flammable gases such as hydrogen, carbon monoxide, or methane. Liquid oxygen can combine with combustible materials and greatly accelerate combustion. Oxygen clings to clothing and cloth items and presents an acute fire hazard.

High Pressure Gas Hazards

In cryogenic systems, high pressures are obtained by gas compression during refrigeration, by pumping of liquids to high pressures followed by rapid evaporation, and by confinement of cryogenic fluids with subsequent evaporation. If this confined fluid is suddenly released through a rupture or break in a line, a significant thrust may be experienced. Over-pressurization of cryogenic equipment can occur due to the phase change from liquid to gas if not vented properly. 

Materials and Construction Hazards 

The selection of materials that come into contact with cryogenics calls for consideration of the effects of low temperatures on the properties of those materials. Some materials become brittle at low temperatures, increasing the risk of equipment failure. Low temperature equipment can also fail due to thermal stresses caused by differential thermal contraction of the materials. 

Cryogenic Safety Guidelines

Responsibilities

Personnel who are responsible for any cryogenic equipment must conduct a safety assessment prior to operating the equipment. Supplementary safety reviews must follow any system modification to ensure that no potentially hazardous condition is overlooked or created and that updated operational and safety procedures remain adequate.

Personal Protective Equipment

Wear the appropriate PPE when working with cryogenic materials. 

• Face shields and splash goggles must be worn during the transfer and normal handling of cryogenic fluids.
• Loose fitting, heavy leather or other cryogenic protective gloves must be worn when handling cryogenic fluids.
• Long shirt sleeves should be rolled down and buttoned over glove cuffs, or an equivalent protection such as a lab coat, should be worn in order to prevent liquid from spraying or spilling inside the gloves.
• Long pants without cuffs should be worn.

Safety Practices

Cryogenic fluids must be handled and stored only in containers and systems specifically designed for these products and in accordance with applicable standards, procedures, and proven safe practices.

Transfer operations involving open cryogenic containers such as dewars must be conducted slowly to minimize boiling and splashing of the cryogenic fluid. Transfer of cryogenic fluids from open containers must occur below chest level of the person pouring the liquid.

Only conduct such operations in well-ventilated areas, such as the laboratory, to prevent possible gas or vapor accumulation that may produce an oxygen-deficient atmosphere and lead to asphyxiation. If this is not possible, an oxygen meter must be installed.

Equipment and systems designed for the storage, transfer, and dispensing of cryogenic fluids need to be constructed of materials compatible with the products being handled and the temperatures encountered.

All cryogenic systems must be equipped with pressure relief devices to prevent excessive pressure build-up. Pressure reliefs must be directed to a safe location. It should be noted that two closed valves in a line form a closed system. 

The caps of liquid nitrogen dewars are designed to fit snugly while still allowing periodic venting to prevent over-pressurization. Never attempt to seal these caps, as doing so can create a serious hazard. Sealing the dewar can lead to dangerous pressure buildup, potentially rupturing the container and causing splashes of liquid nitrogen. In some cases, a large spill could rapidly vaporize and displace oxygen in the area, causing an oxygen-deficient atmosphere. 

If liquid nitrogen or helium traps are used to remove condensable gas impurities from a vacuum system that may be closed off by valves, the condensed gases will be released when the trap warms up. Adequate means for relieving resultant build-up of pressure must be provided.

First Aid

Workers will rarely, if ever, come into contact with cryogenic fluids if proper handling procedures are used. In the unlikely event of contact with a cryogenic liquid or gas, a contact “burn” may occur. The skin or eye tissue will freeze.

If the cryogenic fluid comes in contact with the skin or eyes, flush the affected area with generous quantities of cold water. Never use dry heat. Splashes on bare skin cause a stinging sensation, but, in general, are not harmful.

If clothing becomes soaked with liquid, it should be removed as quickly as possible and the affected area should be flooded with water as above. Where clothing has frozen to the underlying skin, cold water should be poured on the area, but no attempt should be made to remove the clothing until it is completely free.

Seek medical attention immediately if further assistance is needed. Make sure to complete a Workplace Injury Report.

Cryogenic Chemical-Specific Information

Liquid Helium

Liquid helium must be made with helium pressurized, insulated lines. Air solidifies on contact which can lead to over-pressurization. All liquid helium containers must be equipped with a pressure-relief device. The latent heat of vaporization of liquid helium is extremely low (20.5 J/gm); therefore, small heat leaks can cause rapid pressure rises.

Liquid Nitrogen

When transferring liquid nitrogen from open containers (such as wide-mouth dewars), always pour slowly to reduce splashing and excessive boiling. All transfers should be performed below chest level to prevent vapor from contacting the face. Since the boiling point of liquid nitrogen is below that of liquid oxygen, it is possible for oxygen to condense on any surface cooled by liquid nitrogen. If the system is then sealed and the liquid nitrogen is removed, the condensed oxygen may rapidly evaporate. This can lead to over-pressurization of the equipment or a chemical explosion, especially if the oxygen comes into contact with combustible materials such as vacuum pump oil. 

If this oxygen-rich mixture is exposed to radiation, ozone is formed. Ozone may freeze into a highly unstable ice that can explode if disturbed. For this reason, air must not be admitted into enclosed equipment that is below the boiling point of oxygen unless this step is explicitly  required by a written procedure.

When transferring liquid nitrogen from open containers (such as wide-mouth dewars), always pour slowly to reduce splashing and excessive boiling. All transfers should be performed below chest level to prevent vapor from contacting the face. 

Liquid Hydrogen

Anyone planning to use liquid hydrogen must contact EHS at 541-346-3192 to ensure all regulatory and safety requirements have been addressed. 

Due to its extremely wide flammability range and low ignition energy, liquid hydrogen requires stringent safety measures. Transfers must be conducted using helium pressurization through properly designed, vacuum-insulated, and certified transfer lines to prevent contact with air and reduce explosion risk.

Only trained personnel familiar with the properties of liquid hydrogen, associated equipment, and safe operating procedures are permitted to perform transfer operations. All transfer lines must be purged with helium or gaseous hydrogen, using proper safety precautions prior to use. 

The core safety principles for working with liquid hydrogen include:

• Isolation of the experiment from surrounding areas.
• Adequate ventilation to prevent accumulation of hydrogen gas.
• Exclusion of ignition sources and proper system grounding/bonding to avoid static discharge.
• Containment in helium purged vessels.
• Continuous monitoring for hydrogen leakage.
• Limiting the amount of hydrogen pumped in the vacuum system.

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Extractions and Distillations 

Extractions

• Do not attempt to extract a solution until it is cooler than the boiling point of the extractant due to the risk of over pressurization, which could cause the vessel to burst.
• When a volatile solvent is used, the solution should be swirled and vented repeatedly to reduce pressure before separation. Venting should always take place with the stopcock pointed away from the body.
• When opening the stopcock, your hand should keep the plug firmly in place.
• The stopcock should be lubricated.
• Vent funnels away from ignition sources and people, preferably into a hood.
• Keep volumes small to reduce the risk of overpressure and if large volumes are needed, break them up into smaller batches.

Distillations

Avoid bumping (sudden, violent boiling) which can shatter glassware and cause splashes. Use even heating methods such as a heat mantle or water/oil bath. Stirring the solution also helps reduce bumping. 

Only use boiling stones at atmospheric pressure and never add them to hot or near boiling liquid. This can cause immediate boiling and overflow. Never allow organic compounds to boil to dryness unless they are confirmed to be free of peroxides. Boiling to dryness can concentrate peroxides and create an explosion hazard.

Distillation Under Reduced Pressure

• Avoid overheating the liquid. Superheating can lead to decomposition or uncontrolled reactions.
• Bumping is more likely at reduced pressure. Ensure gentle, even heating, and consider inserting a nitrogen bleed tube to minimize pressure fluctuations.
• Evacuate the apparatus gradually to reduce the risk of sudden boiling.
• After distillation, allow the system to cool completely before slowly bleeding in air. If possible, use nitrogen instead of air, as introducing air into a hot system can cause an explosion.
• Refer to the Glass Under Vacuum Section for vacuum safety guidelines.

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Glassware Considerations

General Guidelines for use of Glass Under Vacuum

• Inspect all glassware before use under reduced pressure. Do not sure any glass with chips, cracks, or other defects that could compromise structural integrity.
• Only use glassware specifically rated for vacuum applications. Do not use thin walled or flat bottom flasks unless they are heavy walled filter flasks designed for low pressure. should be used.
• Use a protective shield between the user and vacuum glassware, or wrap glassware with tape to contain fragments in the event of an implosion.
• Hand-blown glassware must not be used under vacuum unless it has been properly annealed to relieve internal stress.

Vacuum pumps

• Use cold traps to prevent contamination of pump oil, which can turn into  hazardous waste.
• Vent pump exhaust into a chemical fume hood whenever possible to avoid exposure to vapors.
• Ensure that all belts and moving parts are properly guarded to prevent injury.
• Always follow appropriate lockout/tagout procedures when servicing vacuum pumps. 

Glassware Washing

In most cases laboratory glassware can be cleaned effectively by using detergents and water. In some cases, it may be necessary to use strong chemicals for cleaning glassware. Strong acids should be avoided unless necessary. Chromic acid should not be used due to its toxicity and disposal concerns. A safer alternative is Alnochromix Reagent, a "concentrated inorganic persulfate based additive to sulfuric acid to make a metal-free and surfactant-free glassware cleaner. It is a nonmetallic, non-carcinogenic, and easier to dispose replacement for chromic acid."

Acid/base baths should have appropriate labeling and secondary containment. Additionally a Standard Operating Procedure (SOP), proper PPE, and spill materials should be available. 

Always inspect glassware for cracks and chips before washing, autoclaving, or use. Dispose of chipped and broken glassware immediately in an approved collection unit. DO NOT put broken glassware in the regular trash. 

Handle glassware with care. Avoid impacts, scratches, or intense heating of glassware.  Use the appropriate labware for the procedures and chemicals. Use care when inserting glass tubing into stoppers: use glass tubing that has been fire-polished, lubricate the glass, and protect your hands with heavy gloves.

If your department/building has a glass washing service follow their policies and regulations as to labeling and emptying glassware.

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Equipment and Apparatus Set Up

General guidelines for setting up Lab apparatus and equipment. 

Glassware

Borosilicate glassware (i.e., Pyrex) is recommended for most lab applications, except for special experiments using UV or other light sources. Soft glass should be reserved for items such as reagent bottles, measuring cylinders, stirring rods, and tubing - not for apparatus exposed to heat or pressure. Glassware used under vacuum (e.g. suction flasks) must be specifically designed with heavy walls to withstand pressure differentials. Glass containers containing hazardous chemicals should be transported in rubber bottle carriers or buckets to prevent breakage and contain any spills or leaks. It is also recommended to transport plastics containers in this manner, as they can similarly break or leak. 

Preparation of Glass Tubing and Stoppers

To cut glass tubing:

• Hold the tube against a firm surface and make one firm quick stroke with a sharp triangular file or glass cutter to score the glass long enough to extend approximately one third around the circumference.
• Cover the tubing with cloth and hold the tubing in both hands away from the body. Place thumbs on the tubing opposite the nick 2 to 3 cm and extended toward each other.
• Push out on the tubing with the thumbs as you pull the sections apart, but do not deliberately bend the glass with the hands. If the tubing does not break, re-score the tube in the same place and try again. Be careful to not contact anyone nearby with your motion or with long pieces of tubing.

All glass tubing, including stir rods, must be fire polished before use. Unpolished edges can cause cuts and make insertion into stoppers difficult or unsafe. After fire polishing or bending glass, allow sufficient time for it to cool completely before handling, as hot glass can cause burns and may look identical to cold glass. .

When drilling a stopper:

• Use only a sharp borer one size smaller than that which will just slip over the tube to be inserted. For rubber stoppers, lubricate with water or glycerol.
• Holes should be bored by slicing through the stopper, twisting with moderate forward pressure, grasping the stopper only with the fingers, and keeping the hand away from the back of the stopper.
• Keep the index finger of the drilling hand against the barrel of the borer and close to the stopper to stop the borer when it breaks through.
• Preferably, drill only part way through and then finish by drilling from the opposite side.
• Discard a stopper if a hole is irregular or does not fit the inserted tube snugly, if it is cracked, or if it leaks.

Corks should have been previously softened by rolling and kneading. Rubber or cork stoppers should fit into a joint so that one-third to one–half of the stopper is inserted.

When available, glassware with ground joints is preferable. Glass stoppers and joints should be clean, dry and lightly lubricated.

Insertion of Glass Tubes or Rods into Stoppers

The following practices will help prevent accidents:

• Make sure the diameter of the tube or rod is compatible with the diameter of the hose or stopper.
• If not already fire polished, fire polish the end of the glass to be inserted. Let it cool.
• Lubricate the glass. Water may be sufficient, but glycerol is a better lubricant.
• Wear heavy gloves or wrap layers of cloth around the glass and protect the other hand by holding the hose or stopper with a layered cloth pad.
• Hold the glass not more than 5 cm from the end to be inserted.
• Insert the glass with a slight twisting motion, avoiding too much pressure and torque.
• When helpful, use a cork borer as a sleeve for insertion of glass tubes.
• If appropriate, substitute a piece of metal tubing for glass tubing.
• Remove stuck tubes by slitting the hose or stopper with a sharp knife

Assembling Apparatus

Following these recommendations will help ensure safer and more effective apparatus assembly:

• Keep your work space free of clutter.
• Set up clean, dry apparatus that is firmly clamped and positioned well back from the edge of the lab bench. Allow adequate space between your setup and others'. As a general rule, leave about 20% free space around your apparatus.
• Choose equipment sizes that are appropriate for intended operation.
• Use only equipment that is free from flaws such as cracks, chips, frayed wire, and other defects. Examine glassware under polarized light to detect internal strains. Even small cracks or chips can render glassware unsafe and should be repaired or discarded.
• Place a properly sized pan beneath reaction vessels or containers to serve as a secondary containment in the event of spills or breakage.
• When working with flammable gases or liquids, keep ignition sources such as burners away. Use appropriate traps, condensers, or scrubbers to minimize environmental release. If using a hot plate, ensure all exposed surfaces remain below the autoignition temperature of the chemicals likely to be released. Confirm that the temperature control device and any motors (stirring or ventilation) do not spark.
• Whenever possible, use controlled electrical heaters or steam in place of gas burners.
• Support addition and separatory funnels securely. Orient them so that gravity will not loosen the stopcock plug. Use a retainer ring on the stopcock plug. Glass stopcocks should be freshly lubricated. Teflon stopcocks should not be lubricated.
• Condensers should be properly supported with securely positioned clamps and the attached water hoses secured with wire or clamps.
• Stirrer motors and vessels should be secured to maintain proper alignment. Magnetic stirring is preferable. Only non-sparking motors should be used in chemical laboratories. Air motors may be an option.
• When using a ring stand, position the apparatus so the system's center of gravity is directly over the base. Ensure heavy-load standards are securely attached to the benchtop. Equipment racks should be firmly anchored at both the top and bottom. Ensure quick removal is possible for burners or baths in case of emergency.
• Do not place apparatus, equipment, or chemical bottles directly on the floor. If needed, place them under tables and out of aisleways to avoid tripping hazards.
• Never heat a closed container. Provide a vent as part of the apparatus for chemicals that are to be heated. Prior to heating a liquid, place boiling stones in unstirred vessels (except test tubes). If a burner is used, distribute the heat with a ceramic-centered wire gauze. Use the thermometer with its bulb in the boiling liquid if there is the possibility of a dangerous exothermic decomposition as in some distillations. This will provide a warning and may allow time to remove the heat and apply external cooling. The setup should allow for fast removal of heat
• If heating of a closed container is required, only use appropriate pressure-rated thick-walled pressure vessels or equivalent metal pressure reactors. An additional blast shield should be used for safety.
• Whenever hazardous gases or fumes are likely to be evolved, an appropriate gas trap should be used and the operation confined to a fume hood.
• Fume hoods are recommended for all operations in which toxic or flammable vapors are generated as is the case with many distillations. Most vapors have a density greater than air and will settle on a bench top or floor where they may diffuse to a distant burner or ignition source. These vapors will roll out over astonishingly long distances and, if flammable, an ignition can cause a flash back to the source of vapors. Once diluted with significant amounts of air, vapors move in air essentially as air itself.
• Use a hood when working with a system under reduced pressure (which may implode). Close the sash to provide a shield. If a hood is not available, use a standing shield. Shields that can be knocked over must be stabilized with weights or fasteners. Standing shields are preferably secured near the top. Proper eye and face protection must be worn even when using safety shields or fume hoods.

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Heat and Heating Devices

Heat hazards within laboratories can occur from a number of sources. To prevent heat-related injuries:

• Heating devices should be set on stable surfaces, well away from any ignitable materials such as flammable solvents, paper products, and other combustibles.
• Never leave open flames, such as those from Bunsen burners, unattended.
• Avoid placing open flames beneath shelves or low overhangs.
• Do not install heating devices near drench showers or any other water-spraying apparatus due to risks of electrical shock concerns and splattering of hot water.
• Use backup power cutoffs or temperature controllers to prevent overheating. If a backup controller is used, it should include an alarm to notify users if a main controller has failure.
• Plan procedures carefully to ensure reaction temperatures do not lead to violent reactions and always have a cooling method available.
• Post visible signage to warn others of heat hazard and prevent accidental burns.

Laboratory Ovens

Follow these additional precautions when using laboratory ovens:

• Ensure adequate removal of generated heat from the surrounding area.
• If toxic, flammable, or otherwise hazardous chemicals may be released, use only single-pass ovens that exhaust directly out of the lab. Exhaust should not come into contact with electrical components or heating elements.

Heating Baths

Flammable substances must only be heating using a heating mantle or steam bath. When using heating baths ensure the bath is durable and firmly supported.

If the bath contains a combustible liquid, set the thermostat below the liquid's flash point. 

• Check the chemical's Safety Data Sheet to determine its flash point.
• Compare that flashpoint with the anticipated reaction temperature to assess fire risk.

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Heat Stress

Heat stress can occur when working in high temperature environments. If your body is unable to regulate its temperature, it can quickly overheat and suffer some degree of heat stress. Heat stress can develop suddenly and, if left unrecognized or untreated, may result in serious health effects.

Heat stress symptoms range from mild (e.g., fainting, cramps, or heat rash) to severe (e.g., heat exhaustion or heat stroke). 

Mild to moderate heat stress symptoms may include heavy sweating, clammy skin, fatigue, decreased strength or coordination, loss of muscle control, dizziness, nausea, and irritability. Move the affected person to a cool place, provide plenty of fluids, and apply cool compresses to the forehead, neck, and underarms.

Heat Stroke

Heat stroke is a medical emergency. It is the most serious form of heat stress and can occur with little warning. It may cause permanent damage to the brain and other vital organs or result in death. Symptoms of heat stroke may include lack of sweating (though some individual may sweat profusely), body temperature of 103°F or higher, red, hot, and dry skin, rapid and strong pulse, throbbing headache, dizziness, nausea, convulsions, confusion or delirium, loss of consciousness, or coma.

In the case of heat stroke, call 911 immediately.  While waiting for medical help, move the person to a cool area, sponge their skin with cool water, and use fanning to promote evaporation. If they are conscious offer a half-glass of water every 15 minutes. Do not force fluids.

Risks and Prevention

Several conditions can affect your body’s ability to regulate temperature:

• Exposure to radiant heat sources (e.g. the sun, furnaces).
• High humidity, which slows the evaporation of sweat.
• Poor air circulation, reducing sweat evaporation.

Certain individuals are at higher risk, especially if: 

• They are new to physical work in hot environments.
• They are pregnant, ill, overweight, physically unfit, or taking medications that can cause dehydration.
• They have consumed alcohol.
• They have a history of heat stress related illness.

In reduce the risk of heat stress:

• Acclimatize gradually. Increase heat exposure over 4-7 days. Acclimatization is lost after a week away from the heat and must be reestablished.
• Stay hydrated. Drink at least 4-8 ounces of fluid every 15-20 minutes to maintain proper balance in hot or humid environments. Do not wait until you're thirsty, thirst is not a reliable indicator of dehydration.
• Use electrolyte beverages. These are helpful during extended heat exposure or intense physical activity.
• Alternate work and rest cycles. Take breaks in a cooler environment to recover.
• Schedule heavy tasks during cooler parts of the day.
• Avoid alcohol during periods of high heat exposure.
• Eat light meals. Cold and easily digestible foods are better in conditions; avoid heavy, fatty meals.

Learn more about heat stress and prevention tips on the Working and Heat Stress webpage. 

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Hydrofluoric Acid (HF) Safety Precautions

Hydrofluoric acid (HF) is extremely hazardous due to its unique combination of physical, chemical, and toxicological properties. Both anhydrous HF and aqueous HF solutions are clear, colorless, and highly corrosive liquids. When exposed to air, anhydrous HF and concentrated solutions release pungent, toxic fumes that are harmful to inhale. 

HF shares the corrosive characteristics common to mineral acids but it is particularly dangerous due to its ability to penetrate deep into body tissues. The fluoride ion readily passes through the skin, causing severe, delayed pain and deep tissue destruction, including damage to bones. Unlike other acids, pain from HF exposure may not be immediate, making it especially insidious. 

If HF is not treated promptly, the fluoride ion continues to cause tissue damage for hours or even days, which can lead to permanent tissue loss, limb amputation, or death. Immediate application of calcium gluconate gel is critical, as it binds fluoride ions and helps neutralize their toxic effects. For eye or large-area exposure, emergency medical care and systemic calcium treatment may be required. 

• Chemical Name: Hydrofluoric Acid
• Synonyms: HF, Hydrogen Fluoride, Hydrofluoride, Fluoric Acid, Fluorane, Rubigine
• Chemical Family: Inorganic Acid.
• Chemical Formula: HF
• Molecular Weight: 20.0 g/mol
• CAS Number: 7664-39-3
• Physical Data Description: Colorless gas or fuming liquid (below 153°F) with a strong, irritating odor.
• Boiling Point: Anhydrous 67°F (19.5°C) solution in water 234°F (112°C)
• Specific Gravity: 1.2 (H2O = 1)
• Vapor Density: 2.21 (Air = 1)
• Vapor pressure: 14 mm HG at 20 C Odor Threshold: 0.5 – 3 ppm (caution: reported range is very broad)

Toxicological Mechanisms

• Fluoride binds to metal-containing enzymes, thereby inactivating them.
• Fluoride binds to calcium, resulting in severe hypocalcemia.
• Fluoride binds to potassium and magnesium ions, leading to myocardial irritability and arrhythmia.
• Fluoride may be directly toxic to the CNS.

Handling and Personal Protective Equipment

Familiarize yourself with the hazards specific to HF before handling. Read and understand the Safety Data Sheet for HF. 

Always handle HF in a properly functioning fume hood and an area equipped with a safety shower/eyewash.

Recommended PPE:

• Goggles or safety glasses with a plastic face shield.
• Double gloves: Thin disposable gloves (such as 4, 6, or 8 mil blue nitrile glove) used in laboratory operations. These provide a contact barrier only and should be disposed of immediately when contamination is suspected.
• Thicker (10-20 mil) PVC or neoprene gloves provide good resistance to HF but do not provide the necessary dexterity for most lab procedures. Disposable gloves should never be worn without double gloving because of the potential for pinholes and exposure. A combination of double gloves, nitrile and poly, can be used to provide greater protection from a broader range of materials. HF concentrations greater than 30% may not be suitable to handle with nitrile gloves only.
• Acid resistant apron
• Long pants, sleeves, and closed toe shoes (always required when working with corrosives)

HF Exposure Procedures:

In the event of any HF exposure, immediate action is critical. The fluoride ion can continue to penetrate tissue and cause severe, irreversible damage if not rapidly treated. 

1. Shot for help if others are nearby. Alert them to HF spill or exposure.
2. Immediately go to the nearest emergency shower and pull the activation handle.
3. While under the water, remove any contaminated clothing to prevent further skin contact.
4. Flush the affected area with water for at least 15 minutes. Do not interrupt rinsing unless you are alone and need to call for help (after flushing for at least 15 minutes) or trained assistance is available and ready to apply calcium gluconate gel to affected area.
5. After 5 minutes of risking, if help is available and the affected area is limited to the skin (e.g. hand or arm), begin applying calcium gluconate gel to the affected area while continuing to rinse with water. Reapply the gel every 15 minutes until emergency responders take over.
6. If you are alone, call 911 after you have finished flushing for at least 15 minutes.
7. Seek medical attention, even if the affected area seems small or painless. Symptoms may be delayed and serious damage can occur without early treatment.
8. Inform medical personnel that the exposure involved hydrofluoric acid and indicate whether calcium gluconate has been applied. 

Complete a Workplace Injury Report as soon as it is safe and feasible to do so. 

If a person is reluctant to use an emergency shower you can provide a barrier/privacy screen using a lab coat or other piece of clothing. If you are assisting someone else, you should wear gloves to avoid contaminating yourself. When using an emergency shower, do not be concerned about the damage from flooding. The important thing to remember is to keep flushing for 15 minutes. 

If there is a large quantity of chemical spilled or washed off, please contact EHS at 541-346-3192 to see if the rinse water needs to be collected as hazardous waste.

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Mercury Containing Equipment

Elemental mercury (Hg) or liquid mercury may still be found in a variety of lab and industrial equipment including thermometers, barometers, diffusion pumps, sphygmomanometers, thermostats, high intensity microscope bulbs, fluorescent bulbs, UV lamps, batteries, Coulter Counter, boilers, ovens, and welding machines. In many cases, mercury-containing devices can and should be replaced with mercury-free alternatives to reduce hazard potential. Larger or older equipment may present additional challenges, as mercury is sometimes hidden within internal components such as gauges, switches, or sealed tubes, making it difficult to identify without detailed equipment specifications or inspection. 

Key concerns with mercury containing equipment are:

• Mercury exposure and cross-contamination from leaks or spills can be difficult to detect and clean.
• The quantity of mercury often exceeds reportable release thresholds (e.g. state or EPA limits)
• Personnel may be unaware that mercury is present, leading to inadequate training and improper use, maintenance, spill response, transport, or disposal practices.
• Use without appropriate engineering controls or PPE increases the risk of exposure.
• Improper handling can result in significant health, environmental, and legal liabilities. 

To minimize the potential for mercury spills and possible exposures, lab personnel are strongly encouraged to:

• Identify and label “Mercury Containing Equipment”.
• Write a Standard Operating Procedure (SOP) for the use of each piece of equipment containing mercury.
• Train personnel on proper use, maintenance, transport, and disposal.
• Conduct periodic inspections of equipment to ensure no leaks or spills have occurred.
• Consider replacing mercury with alternative components. Contact EHS at 346-3192 to replace mercury thermometers with alcohol thermometers of equivalent range.
• Have available proper PPE such as nitrile gloves and post clear warnings to lab personnel that many glove materials do not protect from mercury.
• Use secondary containment, such as trays as a precaution for spills.
• Plan for emergency such as a spill or release of mercury.
• Decontaminate and remove mercury before long-term storage, transport or disposal.
• For new equipment purchases, attempt to procure instruments with no or little mercury.

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Proper Lighting

A well-lit work area is essential for maintaining a safe laboratory environment. 

• Lighting should provide sufficient illumination for all work areas, 100-200 lumens for laboratories.
• Light bulbs that are mounted low and may be subject to accidental contact should be guarded.
• If there is a risk of electrocution when changing light bulbs, lockout/tagout procedures must be followed.
• For replacement and disposal of standard room lighting (e.g. fluorescent bulbs) contact CPFM Customer Service Center at 346-2319. For disposal of specialty lab bulbs (e.g. UV bulbs or specialty fluorescent bulbs) contact EHS at 346-3192.
• As an energy conservation measure, please turn off lights when leaving your lab.

References 

American Chemical Society. Safety in Academic Chemistry Laboratories.