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Lab Safety Programs, Procedures, & Guides                 

Safety around chemicals in the laboratory requires an understanding of the hazards associated with the chemicals and the equipment involved. Communication of these properties is also an essential aspect of safety and hence, correct and adequate labeling is the key. In addition to an understanding, there should be a desire on the part of the individual for self protection as well as the protection of others.

Personal Protective Equipment  (PPE)

The proper use of personal protective equipment will minimize or eliminate exposure to hazards associated with the procedure. The selection of the appropriate PPE to be utilized must be made after a hazard analysis for the procedure has been performed (Appendix VII, Hazard Assessment/PPE).  


Laboratory operations involving toxic, hazardous or odoriferous materials must be conducted within the hood. Air flow into the hood mixes with emitted contaminants and carries them out the duct. Successful containment minimizes fugitive emissions from the hood. This protects the lab worker and keeps background levels of contaminants in the lab to acceptable concentrations.

Some hoods have been designated for special purposes, such as, radioisotope hoods or perchloric acid hoods.

Specific design and procedures for perchloric acid hoods are required due to the potential danger related to the possible accumulation of perchlorates (see Selected Chemicals of Concern below).

No hood provides perfect containment of materials emitted within the hood. It is always possible to improve hood performance, but perfection is not possible. Therefore, people working in laboratories will be exposed to materials they handle and use. The goal is to minimize that exposure, given constraints of technical and financial feasibility. (see Appendix I, Ventilation 4.3.1)

A fume hood must be utilized whenever flammable, toxic or offensive vapors are a hazard! The best ventilating efficiency is attained with the hood sash closed far enough so as to obtain an air velocity of 120 linear feet per minute. Keeping all items six inches behind the sash line and minimizing the quantity of equipment within the hood area will greatly improve the exhaust effect. The operating condition of a hood should be determined before the hood is put to use. When the hood is not operational, close the hood sash, call Physical Plant Department and notify your supervisor immediately.

Chemical Storage

All chemicals must be organized and stored on shelves or in cabinets where they will not be knocked over. One way to organize chemicals is to store organics by number of carbon atoms and to keep them separate from inorganics, which should not be stored in alphabetical order.
A candidate storage method is shown in Table 2-1. Alphabetical storage is bad practice because incompatible chemicals may be stored side by side.

Table 2.1 Suggested shelf storage pattern           gototop.jpg (908 bytes)

(Taken from Flinn Scientific, Inc., catalog)


Sulfur, Phosphorus, Arsenic Phosphorus


Alcohols, Glycols, etc.


Halides, Sulfates, Sulfites Thiosulfates,
  Phosphates, etc.


Hydrocarbons, Esters, etc.


Amides, Nitrates, (Not Ammonium Nitrate),
  Nitrites, etc.


Ethers, Ketones, etc.


Metals, Hydrides  (Store away from any water.)


Epoxy Compounds, Isocyanates


Hydroxides, Oxides Silicates, etc.


Sulfides, Polysulfides, etc.


Arsenates, Cyanides, etc. (Store above acids.)


Phenol, Cresols


Sulfides, Selenides, Phosphides,
Carbides, Nitrides, etc.


Peroxides, Azides, etc.


Borates, Chromates, Manganates,
Permanganates,  etc.


Acids, Anhydrides, Peracids, etc.


Chlorates, Perchlorates, Chlorites,
  Perchloric Acid, Peroxides, etc.


Acids, except Nitric


(Nitric Acid)

If possible, avoid using the floor since a spill may cause a reaction with the spilled products and the material stored on the floor.


Flammable Liquids 
Table 2.2 Properties of common flammables          gototop.jpg (908 bytes)
Deg. F ( C)
Deg. F (C)
Acetone -138 (-94.6) 133 (56) 0 (-18) IB
Acetonitrile -49 (-45) 179 (82) 42 (6) IB
Benzene 42 (5.5) 176 (80) 12 (-11) IB
n-Butanol -128 (-88.9) 243 (117) 95 (35) IC
Carbon disulfide -166.1 (-110) 115 (46) -22 (-30) IB
Cyclohexane 44 (6.5) 179 (82) 1.4 (-17) IB
p-Dioxane 52 (12) 214 (101) 54 (12) IB
Ethanol -202 (-130) 173 (78) 55.6 (13) IB
Dimethyl Ether -177 (-116) 95 (35) -49 (-45) IA
n-Heptane -130 (-90) 209 (98) 25 (-4) IB
n-Hexane -140 (-96) 156 (69) -9.4 (-23) IB
Methanol -144 (-97.8) 147 (64) 54 (12) IB
M.E.K. -122 (-86) 176 (80) 22 (-30) IB
Octane -69 (-56) 258 (126) 56 (13) IB
n-Pentane -200 (-129) 97 (36) -40 (4) IA
2-Propanol -128 (-89) 1581 (83) 53 (12) IB
THF -162 (-108) 151 (66) 1.4 (-18) IB
Toluene -139 (-95) 231 (111) 40 (4) IB
p-Xylene 58 (14) 281 (138) 77 (25) IC


Classification of Flammables (per OSHA 29 CFR 1910.106(a)):          gototop.jpg (908 bytes)

Flammable Liquids

Class IA Liquids: Having a flash point below 73 degrees F and a boiling point below 100 degrees F
Class IB Liquids: Having a flash point below 73 degrees F and a boiling point at or above 100 degrees F
Class IC Liquids: Having a flash point between 73 and 100 degrees F

Combustible Liquids:

Class II Liquids: Having a flash point between 100 and 140 degrees F
Class III Liquids: Having a flash point at or above 140 degrees F
Class IIIA Liquids: Having a flash point between 140 and 200 degrees F
Class IIIB Liquids: Having a flash point above 200 degrees F


 Flash point: Temperature at which the vapor pressure is sufficient to form an ignitable mixture with the air.
Ignition Temperature: Minimum temperature required to cause self-sustained combustion.


Table 2.3 Maximum Allowable for Flammable Liquids         gototop.jpg (908 bytes)
Flammable Liquids Combustible Liquids
Class Class
Container Material: IA IB IC II  III
Glass/Plastic 1 pt   1qt 1gal 1gal  1gal
Tinplate Can 1gal   5gal   5gal 5gal 5gal
Safety Cans 2gal  5gal   5gal  5gal  5gal  

Abbreviations:  gal-gallons;  qt-quart; &  pt-pints

Flammable Storage Cabinets           gototop.jpg (908 bytes)

A multiplicity of flammable storage cabinets of approved design and construction must be provided for each laboratory for the purpose of holding not more than 60 gallons of Class I (IA,IB,IC) or Class II liquids, nor more than 120 gallons of Class III liquids, OSHA 29 CFR 1910.106(d)(3)(i),(II). (See Tables 2-2 and 2-3).  (Also see NFPA Ratings for common chemicals)

A flammable liquid storage building is provided on campus and managed by Environmental Health and Safety. All excessive quantities of flammable liquids must be stored in this building unless an individual department maintains an approved flammable storage building of its own.

Acids and Bases      gototop.jpg (908 bytes)

Concentrated acids and bases should be stored in trays separated from all other chemicals. They should not be stored in unapproved metal cabinets or on high shelves. Acid and corrosive storage cabinets of approved design and construction must be provided for each laboratory for the purpose of holding a multiplicity of corrosive materials, OSHA 29 CFR 1910.106 (d)(3)(ii)(a),(b), NFPA 30-1977.

Toxic substances must be segregated in a well identified area with local exhaust ventilation. Chemicals which are highly toxic or other chemicals whose containers have been opened must be placed in unbreakable secondary containers. Stored chemicals must be examined periodically (at least annually) for replacement, deterioration, and container integrity, OSHA 29 CFR 1910.1450 Appendix D (b).

Oxidizing Agents     gototop.jpg (908 bytes)

These can react at ambient temperatures when stored near or in contact with reducing materials. Also oxidizing agents may initiate or promote combustion in other materials causing fire. Storage areas should be kept cool and well ventilated.

 1. Peroxides, hydroperoxides and peroxyesters: These compounds are all active oxygen-containing materials which can decompose generating oxygen or oxidizing agents. These materials are chemically unstable to varying degrees.

2. Organic peroxides are among the most hazardous chemicals handled in a laboratory. Many organic compounds, including the following types, are known to form extremely dangerous peroxides.


  - Aldehydes.


  - Ethers, especially cyclic ethers such as Tetrahydrofuran (THF).


  - Compounds containing the allylene (CH2=CHCH2R) structure including most olefins.


  - Ketones.


  - Vinyl and vinylidene compounds, e.g., vinyl acetate and vinylidene chloride.

 3. Other oxidizing agents include chlorates, perchlorates, nitrates and permanganates.

Examples of common materials which form dangerous peroxides upon long exposure to air are: Cyclohexene, Cyclooctene, Decalin, p-Dioxane, Ethyl Ether, Isopropyl Ether, Tetrahydrofuran (THF) and Tetralin.

Chromic Acid

Dichromate in sulfuric acid and other strong acid or oxidizer cleaning solutions should not be used for general cleaning purposes due to liberation of extremely toxic chromyl chlorides. Dichromate/sulfuric acid is approved for use only in fume hoods.

Reactive Metals

Waste sodium and other alkali metals, hydrides of alkali metals and phosphorus are extremely hazardous and should be handled with caution. If in doubt of handling procedures contact your supervisor or the University Safety Office.

Chemical Toxins      gototop.jpg (908 bytes)

1. Cyanides and Nitriles: Cyanides and nitriles are among the most toxic substances encountered in the chemical laboratory. The compounds are toxic if inhaled, ingested or absorbed through the skin. CN- blocks cytochrome oxidase in respiration. You must obtain lab certification from the Department Safety Committee before using cyanides or nitriles (acetonitrile, acrylonitrile).

First Aid Treatment: Amyl nitrite must be properly administered immediately. The person administering the first aid should break open an amyl nitrite ampule and hold it under the victim's nose for about 15 seconds and continue administration until help (911) arrives or until the victim can be taken to the Memorial General Hospital Emergency Room. Cyanides and nitriles should not be used unless amyl nitrite is first obtained from the Health Center.

2. The toxicity of common solvents should be recognized. Solvents requiring special care include:


- Certain aromatic hydrocarbons.


- Esters of organic acids.


- Glycols, glycol esters and glycol ethers.


- Halogenated hydrocarbons.


- Lower alcohols--methanol, ethanol, etc.


- Nitrogenous bases such as amines.


- Benzene should not be used unless absolutely necessary.

3. Do not overlook the toxicity of chemical compounds. It is best to consider every chemical toxic and to protect yourself accordingly. However, some chemicals have such acute toxicity (such as hydrogen sulfide and hydrogen cyanide) that especially careful handling of these is required. Be sure to learn the toxic properties of each chemical potentially present in your experiment. Sax's Dangerous Properties of Industrial Materials and the Material Safety Data Sheets (available from EH&S) are good sources of this information.

Chemical Waste Disposal      gototop.jpg (908 bytes)

Disposal of waste shall be in conformance to federal, state and local regulations. For instance, no solvents, acids, bases or any wastewater having a pH outside the range of 6 and 11 shall be discharged to the sewer. For waste disposal procedures see Appendix II-NMSU Chemical Waste Procedures. For further information and assistance on waste disposal contact the University Safety Office.


All chemicals in the laboratory must be labeled with permanent labels. At a mimium the label should indicate the name of the chemical and any possible hazard associated with the chemical (e.g., flammable, toxic) and possible the proper personal protective equipment (see label requirements per NMSU HazCom Program). Supplier labels must indicate the name, hazard and contact address for more information.  EH&S recommends the use of the NPFA label rating system, example.  (also see NMSU Policy on labeling peroxide formers)

In accordance with Prudent Practices and NMSU Safety Policy (on food & chemicals), all laboratory refrigerators used for storage of chemicals must be marked with the signage indicating that food or drink storage is not allowed (see example signs - no food-drink sign   alternate ).   Refrigerators in break rooms and other areas near labs and research areas that are used for food storage should be marked to prevent storage of chemical, infectous materials, waste or other materials that could contaminate the food stuff (see example sign - no chemical storage   alternate).


Material Safety Data Sheets (MSDS) are an integral part of the Hazard Communication Program (see Chemical Safety - Harard Communication Policy and MSDSs). The MSDS serves to communicate information about the properties of the chemical to the user as well as information necessary for emergency response personnel in the event of a contingency. In addition, MSDS also contain sections on health effects and spill clean-up.
MSDSs for chemicals present in a laboratory must be maintained on file in the laboratory, and should be reviewed periodically, especially when using unfamiliar chemicals. MSDS can be obtained from the manufacturer of the chemical (for MSDS sources - check Internet Resources). For an explanation of some common MSDS terms, see Appendix XV, MSDS Acronyms and Definitions.

Selected Chemicals of Concern       gototop.jpg (908 bytes)

Ethers  (also see NMSU Policy)

The lower molecular weight ethers can be dangerous fire and explosion hazards. They have been shown to react violently with oxidizing agents (9,10,11,12,13,24 as cited in the Hazardous Laboratory Chemicals Disposal Guide, CR. Press, 1991).

Some ethers form explosive peroxides on exposure to air and light. Therefore, old ether containers that have previously been opened pose a serious problem in terms of handling and disposal. To alleviate this problem, EH&S recommends the following steps be followed:

  •  1. Order only the amount of ether required.
     2. Do not open multiple containers simultaneously.
     3. Label on the container the date opened and name of the individual responsible
         (see NMSU Policy on Peroxide Disposal)
     4. Attempt to utilize the ether as soon as possible.
     5. Once the container is empty, rinse with alcohol or other fat solvent. The rinsate will be collected by EH&S for proper disposal.

Perchloric Acid (also see NMSU Policy)

The use of perchloric acid or any perchlorate in any laboratory must be thoroughly evaluated before commencing the process. Perchlorates have a serious record of causing severe explosions among experienced laboratory workers. Thorough training must be completed prior to initiation of any experiment, research and development or process involving perchloric acid.


All work with perchloric acid will be performed in exhaust fume hoods specifically designed and approved for perchlorates. These hoods shall not be used for any other type of processes or research due to the unstable nature of the perchlorates. Refer to the text, CRC Handbook of Laboratory Safety, 4th Edition, by A. Keith Furr, CRC Press, Boca Raton, 1995. The perchloric acid section, begins on page 308. Approximately twenty  situations are also highlighted where some form of perchlorate ignited or exploded unexpectedly.

Any time crystals are found contact EH&S immediately!

Picric Acid

Picric acid poses a risk of explosion by shock, friction, fire or other sources of ignition.

Picric acid forms salts with metals which may be sensitive to friction, impact or heat. Additionally contact with concrete floors may form friction-sensitive calcium salt (B cited in Hazardous Laboratory Chemical Disposal Guide, CRC Press, 1991)

The picric acid crystals should be kept moist with not less than half its own weight of water (Hazardous Laboratory Chemicals disposal Guide, CRC Press, 1991).

Procedures for handling picric acid recommended by EH&S follow:

1. It is important to label the container with the date opened and the name of the individual responsible for the chemical.
2. Order only as much as required.
3. If dry picric acid is found contact Safety Office immediately.

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Spill Management

Hazardous material spill procedures  (modified by EH&S)

Spill/Release Events are divided into three basic categories:

1.  Spills/Releases That Are Immediately Dangerous to Life or Health (IDLH):

A spill/release that, in the opinion of the area supervisor or individual responsible for the chemical or area, poses an immediate health threat to the individual and/or other occupants in the building.  In this case:


Sound the fire alarm, if appropriate.


Call 911 from a safe location and provide the following information to the dispatcher:


Nature of the emergency


Chemical involved




Room number


Remain on scene to meet response personnel and provide additional information.

     An example would be a one-liter spill of benzene or an uncontrolled release of hazardous gas.

2.  Spills/Releases That Can Be Cleaned Up By Area Personnel: 

    Attempt to clean up a spill/release if you and/or your supervisor feel that it is safe to do so.  Guidelines include:


    You are thoroughly familiar with the hazards of the material.  (Reference MSDS)


    You have been trained to deal with spills/releases of the size in question.


    You have the proper Personal Protective Equipment (PPE), should it be necessary.


    The appropriate absorbent/neutralizers are readily available.

    It is essential that you collect all spill clean up waste for proper disposal.  DO NOT PLACE IN OR AROUND THE REGULAR TRASH.  Place the spill clean up waste in a closed container and attach a NMSU Waste/Material Tracking Form if available, or at a minimum label with contents.  Contact Environmental Health and Safety (EH&S) at 646-3327 for waste pick up.

     An example would be a mercury thermometer that breaks but the mercury is contained.

 3.  Spills/Releases That Are Not IDLH But Require Technical Assistance:

    If you or your supervisor feels that you do not have the proper training or equipment necessary to clean up a spill/release then call EH&S direct at 646-3327 or 646-3311 to page EH&S staff through the NMSU Police Department.

    Note: All mercury spills are to be cleared by EH&S. Close the area and call EH&S, after hours report to NMSU campus police (646-3311).  An example would be a thermometer that breaks and scatters mercury across the floor. see (Mercury spill procedures)

    All spills that involve hazardous materials which have or are likely to be released to the Santiary sewers (sink or floor drain) must be reported to NMSU Police at 911 or 646-3311. See Spill Control / Slug Control Information and signage.

    In case of body contact with the spilled material: Remove the contaminated clothing and flush the areas of bodily contact with copious amounts of water for at least 15 minutes.  

Emergency Showers           gototop.jpg (908 bytes)

1. If there is a need to use an emergency shower when the fire alarm has been activated to evacuate the building, move to another shower in another part of the building provided that:

    There is no danger in the area (e.g. fire, or a spreading chemical cloud).
    Someone has been notified about your location and that person will notify the emergency personnel.

  2. If there is imminent danger and the emergency showers in the building cannot be used, the injured party should be moved to the closest shower in a different building.  

Spill Stations          gototop.jpg (908 bytes)

EH&S recommends that a spill station be situated within easy reach of the laboratory. A spill station should contain appropriate absorbent/adsorbent, neutralizers, PPE, etc. A sample of the items to be considered in equipping a spill station are as follows:

Table - Suggested Material for Lab Spills        
• Polyethylene bags • Chemical splash goggles
• Brooms or hand-brush • Mops
• 5 gal. polyethylene buckets • Paper towels
• Respirators with organic, acid, dust caustic cartridges • Chemically resistant coveralls (e.g. polyethylene coated tyvek)
• Plastic dustpan • Detergent soap
• Chemically resistant gloves • Duct tape
• Vermiculite  • Acid neutralizer/Baking Soda
• Base neutralizer

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