Laboratory Safety
Laboratory Safety
This domain tests exposure control, chemical hygiene, and emergency response - the practices an inspector verifies and that protect staff from the hazards of the specimens they handle.
Core rules
- Standard precautions treat all blood and body fluids as infectious. PPE is selected by task: gloves, gown, eye and face protection; remove gloves before touching equipment or door handles.
- The OSHA Bloodborne Pathogens standard requires an exposure control plan, hepatitis B vaccination offered at no cost, training at hire and annually, and post-exposure evaluation.
- Chemical hygiene plans address labeling, safety data sheets, storage by hazard class, and fume hood use for volatile solvents. Formaldehyde is a known carcinogen with an OSHA exposure limit.
- Fire classes: A ordinary combustibles, B flammable liquids, C electrical, D metals, K cooking oils. Match the extinguisher to the class.
- Biological spills: contain, apply an appropriate disinfectant (typically 1:10 bleach, about 10 minutes contact), absorb from the outside inward, then discard as biohazardous waste and wash hands.
Worked example
A 200 mL culture of an unknown Gram-negative rod spills on the bench. Alert others, don gloves and eye protection, cover the spill with absorbent material, and apply freshly prepared 1:10 sodium hypochlorite from the perimeter inward. Allow about 10 minutes of contact, wipe up, place debris in a biohazard bag, disinfect the surface again, and wash hands. Report the exposure and document it; aerosol-generating spills of high-risk agents require evacuation and specialist response.
Traps that cost marks
- Using bleach that has aged past efficacy or is mixed with acid, releasing chlorine gas.
- Assuming gloves replace handwashing.
- Storing oxidizers and flammables together.
- Cleaning a spill from the center outward and spreading contamination.