Lab Safety Manual 1996 - Procedures for Specific Classes of Hazardous Materials

The specific rules and procedures for working with hazardous chemicals, as outlined in the preceding section, give insight into the proper methods for handling materials which pose significant hazards due primarily to their chronic toxicity. However, these specific rules and procedures, along with the general rules for working with chemicals, do not address some of the basic physical hazards which may stem from acute exposure to different types of laboratory chemicals. This section offers some specific guidelines for working with common laboratory chemicals that, for varying reasons, are acutely toxic in the sense that they may cause considerable harm to human life and health pending short-term exposures. This section will address five fundamental classes of laboratory chemicals: flammables, corrosives, oxidizers, reactives, and compressed gases. These classes of chemicals may include chemicals that are also covered in the previous section regarding their property of toxicity.

1. Flammable Solvents

(a) Terms and Definitions

Flammable liquids are indeed the most common chemicals found in a laboratory. The primary hazard associated with flammable liquids is, of course, their ability to readily ignite and burn. One should note that it is the vapor of a flammable liquid, not the liquid itself, that ignites and causes a fire.

1. The rate at which a liquid vaporizes is a function of its vapor pressure. In general, liquids with high vapor pressures evaporate at a higher rate compared to liquids of lower vapor pressure. It should be noted that the vapor pressure increases rapidly as the temperature is raised as does the evaporation rate. A reduced-pressure environment also accelerates the rate of evaporation.

2. The flash point of a liquid is the lowest temperature at which a liquid gives off vapor at such a rate as to form an air:vapor mixture that will ignite, but will not sustain ignition. Many commonly used flammable solvents have flashpoints significantly lower than room temperature:

Compound	Flash Point (°C)
diethyl ether	- 45.0
acetone	- 17.8
isopropyl alcohol	11.7

3. The limits of flammability or explosivity define the range of fuel:air mixtures that will sustain combustion. The lower limit of this range is called the Lower Explosive Limit or LEL, and the higher limit of this range is called the Upper Explosive Limit or UEL. Materials with very broad flammability ranges (e.g., acetylene, LEL = 3%, UEL = 65%) are particularly treacherous due to the fact that virtually any fuel:air combination may form an explosive atmosphere.

4. The vapor density of a flammable material is the density (mass to volume ratio) of the corresponding vapor relative to air under specific temperature and pressure conditions. Flammable vapors with densities greater than unity (and thus "heavier" than air) are potentially lethal because they will accumulate at floor level and flow, with remarkable ease, in much the same manner that a liquid would. The obvious threat is that these mobile vapors may eventually reach an ignition source, such as an electrical outlet or a Bunsen burner at another student's bench.

(b) Examples of Flammable Liquids

acetone

ethyl ether

toluene

methyl formate

1. Flammable liquids that are not in active use must be stored in safe containers inside fire resistant storage cabinets designed for flammables, or inside storage rooms.

2. Minimize the amount of flammable liquids stored in the lab.

3. Use flammables only in areas free of ignition sources. Remember, smoking is not permitted inside any University building.

4. The transfer of material to or from a metal container is generally accompanied by an accumulation of static charge on the container. This fact must be kept in mind when transferring flammable liquids, since the discharge of this static charge could generate a spark, thereby igniting the liquid. To make these transfers safer, flammable liquid dispensing and receiving containers must be bonded together before pouring. Large containers such as drums must also be grounded when used as dispensing or receiving vessels. All grounding and bonding connections must be metal to metal. (The aforementioned bonding and grounding wires may be found in most lab safety catalogs.)

5. Never heat flammables with an open flame. Instead, use steam baths, water baths, oil baths, hot air baths, sand baths or heating mantles.

6. Never store flammable chemicals in a standard household refrigerator. There are several ignition sources located inside a standard refrigerator that can set off a fire or violent explosion. Flammables can only be stored cold in a lab safe or explosion-proof refrigerator. Another alternative is to use an ice bath to chill the chemicals. Remember, there is no safety benefit in storing a flammable chemical in a refrigerator if the flashpoint of that chemical is below the temperature of the refrigerator.

(d) Health Hazards Associated with Flammables

In general, the vapors of many flammables are irritating to mucous membranes of the respiratory system and eyes, and in high concentrations are narcotic. The following symptoms are typical for the respective routes of entry.

Acute Health Effects:

Inhalation - headache, fatigue, dizziness, drowsiness, narcosis (stupor and unresponsiveness)

Ingestion - slight gastro-intestinal irritation, dizziness, fatigue

Skin Contact - dry, cracked, and chapped skin

Eye Contact - stinging, watering eyes, and inflammation of the eyelids

Chronic Health Effects:

The chronic health effects will vary depending on the specific chemical, the duration of the exposure, and the extent of the exposure. However, damage to the lungs, liver, kidneys, heart and/or central nervous system may occur. Cancer and reproductive effects are also possible.

Flammable Groups Exhibiting Similar Health Effects:

Hydrocarbons - aliphatic hydrocarbons are narcotic but their systemic toxicity is relatively low. Aromatic hydrocarbons are all potent narcotic agents and overexposure to the vapors can lead to loss of muscular coordination, collapse, and unconsciousness. Benzene is toxic to bone marrow and can cause leukemia.

Alcohols - vapors only moderately narcotic.

Ethers - exhibit strong narcotic properties but for the most part are only moderately toxic.

Esters - vapors may result in irritation to the eyes, nose, and upper respiratory tract.

Ketones - systemic toxicity is generally not high.

(e) First Aid Procedures for Exposures to Flammable Materials

Inhalation Exposures - remove person from the contaminated area if it is safe to do so. Get medical attention and do not leave person unattended.

Ingestion Exposures - remove the person, if possible, from the source of contamination. Get medical attention.

Dermal Exposures - remove person from source of contamination. Remove clothing, jewelry, and shoes from the affected areas. Flush the affected area with water for at least 15 minutes and obtain medical attention.

Eye Contact - remove person from the source of contamination. Flush the eyes with water for at least 15 minutes. Obtain medical attention.

(f) Personal Protective Equipment

Always use a fume hood while working with flammable liquids. Nitrile and neoprene gloves are effective against most flammables. Wear a non-flammable lab coat to provide a barrier to your skin and goggles if splashing is likely to occur (also see Appendix XI for glove information).

2. Oxidizers

(a) General Characteristics

1. Oxidizers or oxidizing agents present fire and explosion hazards on contact with combustible materials. Depending on the class, an oxidizing material may increase the burning rate of combustibles with which it comes in contact; cause the spontaneous ignition of combustibles with which it comes in contact; or undergo an explosive reaction when exposed to heat, shock, or friction.

2. Oxidizers are generally corrosive.

(b) Examples of Common Oxidizers

peroxides	nitrates
nitrites	perchlorates
chlorates	chlorites
hypochlorites	dichromates

1. In general, store oxidizers away from flammables, organic compounds, and combustible materials.

2. Strong oxidizing agents like chromic acid should be stored in glass or some other inert container, preferably unbreakable. Corks and rubber stoppers should not be used.

3. Reaction vessels containing appreciable amounts of oxidizing material should never be heated in oil baths, but rather on a heating mantle or sand bath.

(d) Use and Storage of Perchloric Acid

1. Perchloric acid is an oxidizing agent of particular concern. The oxidizing power of perchloric acid increases with an increase in concentration and with an increase in temperature. Cold, 70% perchloric acid is a strong, non-oxidizing corrosive. A 72% perchloric acid solution at elevated temperatures is a strong oxidizing agent. An 85% perchloric acid solution is a strong oxidizer at room temperature.

2. Do not attempt to heat perchloric acid if you do not have access to a properly functioning perchloric acid fume hood. Perchloric acid can only be heated in a hood specially equipped with a washdown system to remove any perchloric acid residue. The hood should be washed down after each use and it is preferred to dedicate the hood to perchloric acid use only.

3. Whenever possible, substitute a less hazardous chemical for perchloric acid.

4. Perchloric acid can be stored in a perchloric acid fume hood. Keep only the minimum amount necessary for your work. Another acceptable storage site for perchloric acid is on a metal shelf or in a metal cabinet away from organic or flammable materials. A bottle of perchloric acid should also be stored in a glass secondary container to contain leakage.

5. Do not allow perchloric acid to come in contact with any strong dehydrating agents such as sulfuric acid. The dehydration of perchloric acid is a severe fire and explosion hazard.

6. Do not order or use anhydrous perchloric acid. It is unstable at room temperature and can decompose spontaneously with a severe explosion. Anhydrous perchloric acid will explode upon contact with wood.

(e) Health Hazards Associated with Oxidizers

Oxidizers are covered here primarily due to their potential to add to the severity of a fire or to initiate a fire. But there are some generalizations that can be made regarding the health hazards of an oxidizing material. In general, oxidizers are corrosive and many are highly toxic.

Acute Health Effects:

Some oxidizers such as nitric and sulfuric acid vapors, chlorine, and hydrogen peroxide act as irritant gases. All irritant gases can cause inflammation in the surface layer of tissues when in direct contact. They can also cause irritation of the upper airways, conjunctiva, and throat.

Some oxidizers, such as fluorine, can cause severe burns of the skin and mucus membranes. Chlorine trifluoride is extremely toxic and can cause severe burns to tissue.

Nitrogen trioxide is very damaging to tissue, especially the respiratory tract. The symptoms from an exposure to nitrogen trioxide may be delayed for hours, but fatal pulmonary edema may result.

Osmium tetroxide, another oxidant commonly employed in the laboratory, is also dangerous due to its high degree of acute toxicity. It is a severe irritant of both the eyes and the respiratory tract. Inhalation can cause headache, coughing, dizziness, lung damage, difficulty breathing and may be fatal. Osmium tetroxide is regarded by many in the field as having "poor warning properties." This is due to the fact that it is difficult to detect in the atmosphere (by smell or other means). The OHSA-defined Permissible Exposure Limit for osmium tetroxide is 0.0002 ppm, while its odor threshold is 2 ppm - this means that one could conceivably be exposed to osmium tetroxide at concentrations 10,000 times the PEL without knowing it. For this reason, it is recommended that laboratories using osmium tetroxide have necessary safeguards in place before the container is even opened.

Chronic Health Effects:

Nitrobenzene and chromium compounds can cause hematological and neurological changes. Compounds of chromium and manganese can cause liver and kidney disease. Chromium (VI) compounds have been associated with lung cancer.

(f) First Aid

In general, if a person has inhaled, ingested, or come into direct contact with these materials, the person must be removed from the source of contamination as quickly as possible when it is safe to do so. Medical help must be summoned. In the case of an exposure directly to the skin or eyes it is imperative that the exposed person be taken to an emergency shower or eyewash immediately. Flush the affected area for a minimum of 15 minutes, then get medical attention.

(g) Personal Protective Equipment

In many cases, the glove of choice will be neoprene, polyvinyl chloride (PVC), or nitrile. Be sure to consult a glove compatibility chart to ensure the glove material is appropriate for the particular chemical you are working with (see Appendix XI for information on glove suitability and availability).

Goggles must be worn if the potential for splashing exists or if exposure to vapor or gas is likely.

Always use these materials in a chemical fume hood as most pose a hazard via inhalation. Cylinders of compressed gases should be kept in ventilated cabinets.

3. Corrosives

(a) General Characteristics

1. Corrosives are most commonly acids and alkalis, but many other materials can be severely damaging to living tissue.

2. Corrosives can cause visible destruction or irreversible alterations at the site of contact. Inhalation of the vapor or mist can cause severe bronchial irritation. Corrosives are particularly damaging to the skin and eyes.

3. Certain substances considered non-corrosive in their natural dry state are corrosive when wet such as when in contact with moist skin or mucus membranes. An example of these materials are lithium chloride, halogen fluorides, and allyl iodide.

4. Sulfuric acid is a very strong dehydrating agent and nitric acid is a strong oxidizing agent. Dehydrating agents can cause severe burns to the eyes due to their affinity for water.

(b) Examples of Corrosives

sulfuric acid	ammonium bifluoride
chromic acid	bromine
stannic chloride	ammonium hydroxide

1. Always store acids separately from bases. Also, store acids in acid storage cabinets away from flammables since many acids are also strong oxidizers.

2. Do not work with corrosives unless an emergency shower and continuous flow eyewash are available.

3. Add acid to water, but never add water to acid. This is to prevent splashing from the acid due to the generation of excessive heat as the two substances mix.

4. Never store corrosives above eye level. Store on a low shelf or cabinet.

5. It is a good practice to store corrosives in a tray or bucket to contain any leakage.

6. When possible, purchase corrosives in containers that are coated with a protective plastic film that will minimize the danger to personnel if the container is dropped.

7. Store corrosives in a wooden cabinet or one that has a corrosion-resistant lining. Corrosives stored in an ordinary metal cabinet will quickly damage it. If the cabinet supports that hold up the shelves become corroded, the result could be serious. Acids should be stored in acid storage cabinets specially designed to hold them and Nitric acid should be stored in a separate cabinet or compartment

(d) Use and Storage of Hydrofluoric Acid

1. Hydrofluoric acid is extremely hazardous and deserves special mention. Hydrofluoric acid can cause severe burns and inhalation of anhydrous hydrogen fluoride can be fatal. Initial skin contact with hydrofluoric acid may not produce any symptoms.

2. Only persons fully trained in the hazards of hydrofluoric acid should use it.

3. Always use hydrofluoric acid in a properly functioning fume hood. Be sure to wear personal protective clothing!

4. If you suspect that you have come in direct contact with hydrofluoric acid: wash the area with water for at least 15 minutes, remove clothing, then promptly seek medical attention. If hydrogen fluoride vapors are inhaled, move the person immediately to an uncontaminated atmosphere (if safe to do so), keep the person warm, and seek prompt medical attention.

5. Never store hydrofluoric acid in a glass container because it is incompatible with glass.

6. Store hydrofluoric acid separately in an acid storage cabinet and keep only that amount necessary in the lab.

7. Creams for treatment of hydrofluoric acid exposure are commercially available.

(e) Health Hazards Associated with Corrosives

All corrosives possess the property of being severely damaging to living tissues and also attack other materials such as metal.

Skin contact with alkali metal hydroxides, e.g., sodium hydroxide and potassium hydroxide, is more dangerous than with strong acids. Contact with alkali metal hydroxides normally causes deeper tissue damage because there is less pain than with an acid exposure. The exposed person may not wash it off thoroughly enough or seek prompt medical attention.

All hydrogen halides are acids that are serious respiratory irritants and also cause severe burns. Hydrofluoric acid is particularly dangerous. At low concentrations, hydrofluoric acid does not immediately show any signs or symptoms upon contact with skin. It may take several hours for the hydrofluoric acid to penetrate the skin before you would notice a burning sensation. However, by this time permanent damage, such as second and third degree burns with scarring, can result.

Acute Health Effects:

Inhalation - irritation of mucus membranes, difficulty in breathing, fits of coughing, pulmonary edema

Ingestion - irritation and burning sensation of lips, mouth, and throat; pain in swallowing; swelling of the throat; painful abdominal cramps; vomiting; shock; risk of perforation of the stomach

Skin Contact - burning, redness and swelling, painful blisters, profound damage to tissues, and with alkalis; a slippery, soapy feeling

Eye Contact - stinging, watering of eyes, swelling of eyelids, intense pain, ulceration of eyes, loss of eyes or eyesight

Chronic Health Effects:

Symptoms associated with a chronic exposure vary greatly depending on the chemical. For example, the chronic effect of hydrochloric acid is damage to the teeth; the chronic effects of hydrofluoric acid are decreased bone density, fluorosis, and anemia; the chronic effects of sodium hydroxide are unknown.

(f) First Aid

Inhalation - remove person from source of contamination if safe to do so. Get medical attention. Keep person warm and quiet and do not leave unattended.

Ingestion - remove person from source of contamination. Get medical attention and inform emergency responders of the name of the chemical swallowed.

Skin Contact - remove person from source of contamination and take immediately to an emergency shower or source of water. Remove clothing, shoes, socks, and jewelry from affected areas as quickly as possible, cutting them off if necessary. Be careful not to get any chemical on your skin or to inhale the vapors. Flush the affected area with water for a minimum of 15 minutes. Get medical attention.

Eye Contact - remove person from source of contamination and take immediately to an eyewash or source of water. Rinse the eyes for a minimum of 15 minutes. Have the person look up and down and from side to side. Get medical attention. Do not let the person rub their eyes or keep them tightly shut.

(g) Personal Protective Equipment

Always wear the proper gloves when working with acids. Neoprene and nitrile gloves are effective against most acids and bases. Polyvinyl chloride (PVC) is also effective for most acids (see Appendix XI for more glove compatibility information). A rubber coated apron and goggles should also be worn. If splashing is likely to occur, wear a face shield over the goggles. Always use corrosives in a chemical fume hood.

4. Reactives

(a) General Characteristics

Polymerization Reactions - Polymerization is a chemical reaction in which two or more molecules of a substance combine to form repeating structural units of the original molecule. This can result in an extremely high or uncontrolled release of heat. An example of a chemical which can undergo a polymerization reaction is styrene.

Water Reactive Materials

1. When water reactive materials come in contact with water, one or more of the following can occur: liberation of heat which may cause ignition of the chemical itself if it is flammable, or ignition of flammables that are stored nearby; release of a flammable, toxic, or strong oxidizing gas; release of metal oxide fumes; and formation of corrosive acids.

2. Water reactive chemicals can be particularly hazardous to firefighting personnel responding to a fire in a lab, because water is the most commonly used fire extinguishing medium. Examples of water reactive materials:

alkali metals:	silanes
lithium, sodium, potassium	alkylaluminums
magnesium	zinc
	aluminum

Pyrophorics - Pyrophoric materials can ignite spontaneously in the presence of air. Examples of pyrophoric materials:

diethylzinc

triethylaluminum

many organometallic compounds

Peroxide-Forming Materials - Peroxides are very unstable and some chemicals that can form them are commonly used in laboratories. This makes peroxide-forming materials some of the most hazardous substances found in a lab. Peroxide-forming materials are chemicals that react with air, moisture, or impurities to form peroxides. The tendency to form peroxides by most of these materials is greatly increased by evaporation or distillation. Organic peroxides are extremely sensitive to shock, sparks, heat, friction, impact, and light. Many peroxides formed from materials used in laboratories are more shock sensitive than TNT. Just the friction from unscrewing the cap of a container of an ether that has peroxides in it can provide enough energy to cause a severe explosion.

Examples of peroxide-forming materials (the first group listed is the most hazardous):

diisopropyl ether divinylacetylene

sodium amide potassium amide

dioxane diethyl ether

tetrahydrofuran vinyl ethers

butadiene vinylpyridine

acrylonitrile styrene

Note: See Appendix XII for list of more peroxide forming chemicals.

Other Shock-Sensitive Materials - These materials are explosive and sensitive to heat and shock.

Examples of shock-sensitive materials:

chemicals containing nitro groups

fulminates

hydrogen peroxide (30% +)

ammonium perchlorate

benzoyl peroxide (when dry)

Compounds containing the functional groups: acetylide, azide, diazo, halamine, nitroso, and ozonide.

Note: See Appendix XIII for a complete list of potentially explosive chemicals.

(b) Use and Storage of Reactives

1. A good way to reduce the potential risks is to minimize the amount of material used in the experiment. Use only the amount of material necessary to achieve the desired results.

2. Always substitute a less hazardous chemical for a highly reactive chemical whenever possible. If it is necessary to use a highly reactive chemical, order only the amount that is necessary for the work.

Water Reactive Materials

Store water-reactive chemicals in an isolated part of the lab. A cabinet far removed from any water sources, such as sinks, emergency showers, and chillers, is an appropriate location. Clearly label the cabinet "Water-Reactive Chemicals - No Water".

Pyrophorics

Store pyrophorics in an isolated part of the lab and in a clearly marked cabinet. Be sure to routinely check the integrity of the container and have the material disposed of through EH&S if the container is corroded or otherwise damaged.

Peroxide-Forming Materials

1. Do not open the chemical container if peroxide formation is suspected. The act of opening the container could be sufficient to cause a severe explosion. Visually inspect liquid peroxide-forming materials for crystals or unusual viscosity before opening. Pay special attention to the area around the cap. Peroxides usually form upon evaporation, so they will most likely be formed on the threads under the cap.

2. Date all peroxide forming materials with the date received, and the expected shelf life. Chemicals such as diisopropyl ether, divinyl acetylene, sodium amide, and vinylidene chloride should be discarded after three months. Chemicals such as dioxane, diethyl ether, and tetrahydrofuran should be submitted to EH&S for disposal after one year.

3. Store all peroxide-forming materials away from heat, sunlight, and sources of ignition. Sunlight accelerates the formation of peroxides.

4. Secure the lids and caps on these containers to discourage the evaporation and concentration of these chemicals.

5. Never store peroxide-forming materials in glass containers with screw cap lids or glass stoppers. Friction and grinding must be avoided. Also, never store these chemicals in a clear glass bottle where they would be exposed to light.

6. Contamination of an ether by peroxides or hydroperoxides can be detected simply by mixing the ether with 10% (wt/wt) aqueous potassium iodide solution - a yellow color change due to the oxidation of iodide to iodine confirms the presence of peroxides. Small amounts of peroxides can be removed from contaminated ethers via distillation from lithium aluminum hydride (LiAlH-4-), which both reduces the peroxide and removes contaminating water and alcohols. However, if you suspect that peroxides may be present, it would be wise to call EH&S for disposal. If you notice crystal formation in the container or around the cap, do not attempt to open or move the container. Call EH&S for proper disposal.

7. Never distill an ether unless it is known to be free of peroxides.

Other Shock Sensitive Materials

Store these materials separately from other chemicals and in a clearly labeled cabinet.

Never allow picric acid to dry out, as it is extremely explosive. Always store picric acid in a wetted state.

Reactive chemicals are grouped as a category primarily because of the safety hazards associated with their use and storage and not because of similar acute or chronic health effects. For health hazard information on specific reactive materials consult the MSDS, the manufacturer, or EH&S. However, there are some hazards common to the use of reactive materials. Injuries can occur due to heat or flames, inhalation of fumes, vapors, and reaction products, and flying debris.

First Aid

If someone is seriously injured the most important step to take is to contact emergency responders as quickly as possible. This is best accomplished by directly calling them at 9-911. Explain the situation and describe the location clearly and accurately.

If someone is severely bleeding, apply a sterile dressing, clean cloth, or handkerchief to the wound. Then put protective gloves on and place the palm of your hand directly over the wound and apply pressure and keep the person calm. Continue to apply pressure until help arrives.

If a person's clothes are on fire, he or she should drop immediately to the floor and roll. If a fire blanket is available, put it over the individual. An emergency shower, if one is immediately available, can also be used to douse flames.

If a person goes into shock, have the individual lie down on their back if safe to do so and raise the feet about one foot above the floor.

Personal Protective Equipment

Wear appropriate personal protective clothing while working with highly reactive materials. This might include: impact resistant safety glasses or goggles, a face shield, gloves, a lab coat (to minimize injuries from flying glass or an explosive flash), and a shield. Conduct work within a chemical fume hood as much as possible and pull down the sash as far as is practical. While the experiment does not require you to reach into the fume hood, keep the sash closed.

Barriers can offer protection of personnel against explosions and should be used. Many safety catalogs offer commercial shields which are commonly polycarbonate and are weighted at the bottom for stability. It may be necessary to secure the shields firmly to the work surface.

5. Compressed Gas Cylinders

General Characteristics:

1. Cylinders of compressed gases can pose a chemical as well as a physical hazard.

2. If the valve were to break off a cylinder, the amount of force present could propel the cylinder through a brick wall. For example, a cylinder of compressed breathing air used by SCUBA divers has the explosive force of 1 1/2 pounds of TNT.

Purchase Policy

Purchase of gases in non-returnable cylinders is restricted by policy at The University (see Appendix XIV for the Gas Cylinder Policy).

Use and Storage

1. Whenever possible, use flammable and reactive gases in a fume hood or other ventilated enclosure. As noted in Chapter C.2., concerning storage cabinets, certain categories of toxic gases must always be stored and used in ventilated enclosures.

2. Always use the appropriate regulator on a cylinder. If a regulator will not fit a cylinder's valve, replace the cylinder, not the regulator. Do not attempt to adapt or modify a regulator to fit a cylinder it was not designed for. Regulators are designed to fit only specific cylinder valves to avoid improper use.

3. Inspect regulators, pressure relief devices, valves, cylinder connections, and hose lines frequently for damage.

4. Never use a cylinder that cannot be positively identified. Color coding is not a reliable way of identifying a cylinder because the colors can vary from supplier to supplier.

5. Do not use oil or grease on any cylinder component of an oxidizing gas because a fire or explosion can result.

6. Never transfer gases from one cylinder to another. The gas may be incompatible with the residual gas remaining in the cylinder or may be incompatible with the cylinder material.

7. Never completely empty cylinders during lab operations; rather, leave approximately 25 PSI of pressure. This will prevent any residual gas in the cylinder from becoming contaminated. However, if the cylinder is non-returnable, call EH&S Hazardous Materials Division chemists for instructions. If inert, you will be asked to vent the remainder of the gas; if not inert, you may need to react it off. In either of these cases, EH&S will be able to discard the cylinder (after valve removal) at no cost to The University. If venting or reacting is unsafe, EH&S can still dispose of most cylinders.

8. Place all cylinders so that the main valve is always accessible.

9. Close the main cylinder valve whenever the cylinder is not in use.

10. Remove regulators from unused cylinders and always put the safety cap in place to protect the valve.

11. Always secure cylinders, whether empty or full, to prevent them from falling over and damaging the valve (or falling on your foot). Secure cylinders by chaining or strapping them to a wall, lab bench, or other fixed support.

12. Oxygen should be stored in an area that is at least 20 feet away from any flammable or combustible materials or separated from them by a non-combustible barrier at least 5 feet high and having a fire-resistance rating of at least 1/2 hour.

13. To transport a cylinder, put on the safety cap and strap the cylinder to a handtruck in an upright position. Never roll a cylinder.

14. Always clearly mark empty cylinders and store them separately.

15. Be careful while handling compressed gas cylinders and never drop or strike a cylinder against anything.

16. Use only wrenches or other tools supplied by the cylinder supplier to open a valve. Open cylinder valves slowly.

17. Only compatible gases should be stored together in a gas cylinder cabinet.

18. Flammable gases must be stored in properly labelled, secured areas away from possible ignition sources and kept separate from oxidizing gases.

19. Do not store compressed gas cylinders in areas where the temperature can exceed 125F.

References:

CRC Handbook of Laboratory Safety, Third Edition. A. K. Furr, Ed. Chemical Rubber Company. 1990.

First Aid Manual for Chemical Accidents. M. Lefevre. 1989.

Hazardous Waste Operations and Emergency Response for Colleges and Universities, Occupational and Environmental Safety Training Division. Texas Engineering Extension Service, Texas A&M University System.

Hazards in the Chemical Laboratory. L. Bretherick, Ed. 1986.

Matheson Gas Data Book. W. Braker and A. L. Mossman. 1971.

Prudent Practices for Handling Hazardous Chemicals in Laboratories. Prepared by the National Research Council. 1981.

Prudent Practices in the Laboratory. National Research Council. 1995.

Safe Storage and Handling of Laboratory Chemicals - A Review of Safe Storage and Handling Practices for Laboratory Chemicals. Nancy Magnussen. Texas A&M University Chemistry Safety Coordinator.

Safety in Academic Chemistry Laboratories. American Chemical Society. 1990.

The Sigma-Aldrich Library of Chemical Safety Data (Second Edition). R. E. Lenga, Ed. 2 volumes, 1988.

E. Procedures for Specific Classes of Hazardous Materials