University Resources, Operations and Policies

 

Section 7


Section 7.0 Procedure-Specific Safety Procedures

Written laboratory procedures normally have a brief description of specific safety practices for that particular procedure. All personnel should read and understand these practices before commencing a procedure.


7.1 Procedures for Toxic Chemicals
The MSDS for many of the chemicals used in the laboratory will state recommended limits or OSHA-mandated limits, or both, as guidelines for exposure. Typical limits are threshold limit values (TLV), permissible exposure limits (PEL), and action levels. When such limits are stated, they will be used to assist the Chemical Hygiene Officer in determining the safety precautions, control measures, and safety apparel that apply when working with toxic chemicals.    

  1. When TLV or PEL value is less than 50 ppm or 100 mg/m3, the user of the chemical must use it in an operating fume hood, glove box, vacuum line, or similar device, which is equipped with appropriate traps and/or scrubbers. If none are available, no work should be performed using that chemical.
  2. Laboratory work with toxic substances having moderate or greater vapor pressures should be conducted in a fume hood, glove box, vacuum line, or similar device, which is equipped with appropriate traps and/or scrubbers. If none are available, no work should be performed using that chemical.

7.2 Procedures for Flammable Chemicals
In general, the flammability of a chemical is determined by its flash point, the lowest temperature at which an ignition source can cause the chemical to ignite momentarily under certain controlled conditions.

  1. Chemicals with flash points between 100o and 200oF are termed “Combustible.” Chemicals with a flash point below 100°F are “Flammable.”  Any chemical with a flash point below 200°F will be considered a “fire-hazard chemical.”  More detailed discussions on fire hazard chemicals can be found in OSHA regulations (2) and National Fire Prevention Association (NFPA) manuals (3, 4).
  2. Fire-hazard chemicals should be stored in a flammable-solvent storage area or in a storage cabinets designed for flammable materials.
  3. Fire-hazard chemicals should be used only in vented hoods and away from sources of ignition.

7.3 Procedures for Reactive Chemicals
The most complete and reliable references on chemical reactivity is found in “Handbook of Reactive Chemical Hazards” by Bretherick (5). Reactivity information is sometimes given in the manufactures’ MSDS and on labels. Guidelines on which chemicals are reactive can be found in regulations promulgated by the Department of Transportation (DOT) in 49 CFR (6) and by the Environmental Protection Agency (EPA) (7), and also NFPA Manual 325 M (8a), Manual 49, “Hazardous Chemicals Data” (8b); and Manual 491M, “Manual of Hazardous Chemical Reactions” (8c).

  1. A reactive chemical is one that:
    1. Is ranked by the NFPA as 3 or 4 for reactivity;
    2. Is described as such in Bretherick (5) or the MSDS;
    3. Is identified by the DOT as:
      an oxidizer
      an organic peroxide, or
      an explosive, Class A, B, or C;
    4. Fits the EPA definition of reactive (9);
    5. Fits the OSHA definition of unstable (10);
    6. Is known or found to be reactive with other substances.

Handle reactive chemicals with all proper safety precautions, including segregation in storage and prohibition on mixing even small quantities with other chemicals without appropriate personal protection and precaution.


7.4 Procedures for Corrosive Chemicals and Contact-Hazard Chemicals
Corrosivity, allergenic, and sensitizer information is sometimes given in the manufactures’ MSDS and on labels. Also, guidelines on which chemicals are corrosive can be found in other OSHA standard and in regulations promulgated by the DOT in 49 CFR and the EPA in 40 CFR.

  1. A corrosive chemical is one that :
    1. Fits the OSHA definition of corrosive (11);
    2. Fits the EPA definition of corrosive (12) (has a pH greater than 12 or less than 2,5); or
    3. Is known or found to be corrosive on living tissues. 
  2. A contact-hazard chemical is an allergen or sensitizer that:
    1. Is so identified or described in the MSDS or on the label;
    2. Is so identified or described in the medical or industrial hygiene literature; or
    3. Is known or found to be an allergen or sanitizer. 
  3. Handle corrosive and contact-hazard chemicals with all proper safety precautions, including wearing both safety goggles and face shield, gloves tested for absence of pin holes and known to be resistant to permeation or penetration, and a laboratory apron or laboratory coat.

Contact:

Joseph Landesberg, Ph.D.
Chemical Hygiene Officer
p – 516.877.4148
e – landesbe@adelphi.edu

 
 
 
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