General Lab Safety Rules

Awareness is the most fundamental principle of laboratory safety:
  • The hypothetical question What would happen if…? should always be posed before an experiment or procedure is attempted.  Do not conduct the procedure unless you can answer all “What if” questions.
  • Never underestimate the risk and hazards involved in working in laboratories.
  • Plan ahead.  Review thoroughly all proposed laboratory procedures to determine the potential health and safety hazards before you begin work.
  • Assume that substances of unknown toxicity are hazardous.
  • Assume that a mixture will be more toxic than its most toxic component.
  • Be alert to unsafe conditions and ensure that they are corrected as soon as they are detected.
  • Be prepared for accidents or unexpected events.
    • Before beginning an experiment, know what specific action to take in the event of an accidental release of a hazardous substance or an injury.
    • Always know the location of safety equipment in your area, and the emergency safety procedures and contact numbers for your area.
    • If a test result is different than the predicted, a review of how the new result impacts safety practices must be made.
General Rules:
  • In addition to the rules and guidelines presented here, a best practice is to consult Prudent Practices in the Laboratory as the authoritative external laboratory safety reference.
  • Make sure that all containers are properly labeled.
  • A fume hood or other containment device (glove box, etc.) must be used if exposure limits are likely to be exceeded, or if uncertainty exists.
    • Because odor thresholds can be greater than the exposure limits, odors should not be used as the primary method of vapor detection.
    • If suspicious odors are noticed, the laboratory worker should contact the CHO immediately.
    • Use a Fume Hood if the TWA is below 50 ppm or 100 mg/m (Prudent Practices, p. 60).
  • Avoid inhalation of chemicals; do not “sniff-test” chemicals.
    • If you need to smell a vapor then do not put your nose directly above a flask, beaker, or other vessel that contains chemicals.
    • Holding the vessel at least one foot away, use you hand to gently and very cautiously fan the vapors towards your nose.
  • PPE and Personal Attire.  Wear appropriate Personal Protective Equipment and Personal Attire at all times.  Chemical splash goggles must be provided to all laboratory visitors; visitors must also wear appropriate personal attire and PPE.
  • No Food, Tobacco, Cosmetics:
    • Never eat, drink, chew gum, smoke, or apply cosmetics in laboratories or chemical storage areas.
    • Food, beverage, or tobacco products are not allowed in laboratories or chemical storage areas.  Food, drink, and especially tobacco absorb chemical vapors, particulates, and gases from the air.
  • Hold reagent bottles and other vessels containing liquids so that any drips will be opposite the label, and hold them so any previous drips on that same side do not get on your hand. Clean off any drips or spills.
  • Avoid accidental self-injection of chemicals (be careful with sharp objects!).
  • Never taste chemicals.
  • Never use mouth suction to pipette chemicals; use suction bulbs or other mechanical devices.
  • Only use glassware or utensils for their intended purposes (e.g., do not use a beaker as a drinking glass).
  • Handle and store laboratory glassware with care to avoid damage.
  • Inspect glassware often; do not use damaged glassware.
  • Use extra precautions when handling containers that are under negative or positive pressure; shield or wrap them to contain chemicals and fragments should an explosion/implosion occur.
  • Avoid practical jokes or other behavior that might confuse, startle, or distract another worker.  Any “horseplay” or behavior that is harassing, disruptive, aggressive, or in any way presents a hazard to those working in the laboratory is forbidden.  Any person or groups of persons engaging in such behavior will be required to leave the laboratory.
  • Vent equipment that may discharge harmful vapors or mists (vacuum pumps, distillation columns) into fume hoods or snorkel hoods.
  • Do not allow the release of toxic substances into cold rooms since these rooms recirculate the air.
  • Immediately clean up all spills and properly dispose of the spilled chemical.
  • Hazardous Waste.  Deposit chemical wastes in appropriately labeled receptacles and follow all protocols, including proper labeling, for the disposal of waste chemicals.
  • Never add water to acids or bases. Dilute concentrated acids and bases by slowly pouring the acid or base into the water while stirring.
    • Combining acid and water frequently generates heat and may cause splashing.
    • Adding the acid to the water reduces the amount of heat generated at the point of mixing and provides more water to disperse the heat.
  • Benchtop Safety Shields. Note that the use of a closed fume hood sash may suffice, but realize that there may be situations when a safety shield (or a section of the horizontal fume hood sash) might need to be used inside a fume hood.  The shield must be placed between the apparatus and the worker.  These shields (in addition to chemical splash-resistant goggles) must be used when:
    • A higher-than-normal splash hazard exists (e.g., heating concentrated corrosives).
    • The contents are under a sufficiently strong positive or negative pressure that, should the vessel break, debris from an unprotected container could be projected about the lab.
Fundamental Steps to Follow Before Working with Hazardous Substances:
  • Hazard Identification.
    • Consult the label, SDS, and other sources for information to evaluate the hazardous properties of a chemical, including routes of exposure and exposure limits.
    • Determine if a less hazardous (or nonhazardous) chemical can be substituted.
  • Characteristics of the Chemical.  Laboratory workers must know the following:
    • Physical properties of the chemical (e.g., aerosol, liquid, low vapor pressure that can lead to fast evaporation and increase exposure)
    • Type(s) of hazard (corrosive, flammable, toxic, etc.)
    • Chemical incompatibilities (e.g., mixing of certain chemicals can cause fires, release of toxic fumes, etc.)
    • Route(s) of exposure (inhalation, absorption through skin, ingestion, injection)
    • The amount of exposure that is considered to be safe
    • The lethal dose of any toxic chemical
    • How the chemical acts on the body (acute or chronic; carcinogen; mutagen; teratogen)
    • Symptoms and target organs of over-exposure
  • Identify the Circumstances of Use.
    • Calculate the amounts to be used or the possibility of generating new or unknown substances.
    • Plan the positioning of equipment before beginning any new operation.
    • Review thoroughly all proposed laboratory procedures to determine the potential health and safety hazards before you begin work.
    • Is it possible for new or unknown substances to be generated?
    • Are any chemicals known to cause birth defects, etc.?
    • Do any workers have known sensitivities to specific chemicals?
    • What is the knowledge/comfort level of the laboratory workers?
  • Standard Operating Procedures.  For any chemical that is defined as hazardous, the SOPs for working with that type of hazard must be followed in addition to the safety rules outlined in this chapter.
  • Follow all safeguards for using the chemicals including:
    • When and how to use control measures (fume hoods, etc.).
    • Appropriate personal protective clothing and equipment.
    • How and where to properly place the chemical when in use.
    • How and where to properly store the chemical when not in use.
    • The proper methods of handling & moving chemicals.
    • The proper procedures for handling chemical wastes .
    • Regularly inspect laboratory equipment. Do not use if the item is even suspected to be defective.
  • Prior Approval.  Obtain approval for using the chemicals listed in Section 7.1.i(1) of the Chemical Hygiene Plan before using them.
  • Particularly Hazardous Substances.
    • OSHA recognizes certain groups of chemicals as being “particularly hazardous” and requires that specific provisions be followed.  These substances include (a) ‘select carcinogens’, (b) reproductive toxins, and (c) substances that have a high degree of acute toxicity. See Section 8.17 of the CHP for more information.
    • Faculty/Staff who intend to use these chemicals must inform the CHO and Department Chair at the time the order is placed regarding its intended use, standard operating procedures, storage, etc.
Avoid/Minimize Exposure to Hazardous Substances:
  •  Do Not Exceed the Exposure Limits: PEL (Permissible Exposure Limit), TLV (Threshold Limit Value), and BEI (Biological Exposure Indices).  Substances can be hazardous simply by being exposed to the atmosphere because the harmful vapors can then come in contact with or be absorbed into a person’s body.
  • Implement Control Measures.  Control Measures are actions aimed to eliminate a hazard.  Continually implement the Hierarchy of Controls to select the best control to mitigate the risk of an accident, incident, injury, or near-miss in the laboratory.