Laboratory Safety and Infection Control
Laboratory Safety and Infection Control tests hazard recognition, routine practices, additional precautions, and correct response to spills, exposures and emergencies. The exam favours scenarios in which an obvious action is also a wrong one - for example, recapping a needle or mopping a blood spill with alcohol.
Hazard communication
WHMIS 2015 aligns with the GHS: supplier labels carry a product identifier, hazard pictograms, a signal word, hazard statements and precautionary statements, and every hazardous product has a 16-section Safety Data Sheet. Know where SDSs are kept and check them before handling an unfamiliar chemical such as formaldehyde, glutaraldehyde or xylene.
Routine practices and PPE
Treat all blood and body fluids as potentially infectious. Gloves for contact, gown for splash risk, eye and face protection as needed; never reuse single-use PPE. Clean hands with soap and water for 40–60 seconds, or alcohol-based rub for 20–30 seconds when hands are not visibly soiled - soap and water is required for C. difficile and norovirus. Additional precautions: contact (MRSA, VRE, C. difficile), droplet (influenza, pertussis, meningococcal), airborne (TB, measles, varicella) - the last requires a fit-tested N95 respirator.
Sharps and spills
Do not recap, bend or break needles; activate the safety device and place the sharp in a puncture-resistant container at the point of use, replacing it when about three-quarters full. For a blood spill: don PPE, absorb the bulk, cover with 1:10 household bleach (about 0.5% sodium hypochlorite) for 10 minutes' contact, wipe up and discard as biomedical waste. A centrifuge breakage means keeping the lid closed for 30 minutes so aerosols settle before opening.
Transport and emergencies
Biological substances shipped as Category B use UN3373 and triple packaging: primary receptacle, absorbent material, secondary packaging, rigid outer package. Fire response uses RACE and PASS; chemical eye exposure requires flushing at an eyewash for at least 15 minutes.
Worked example
A tube breaks inside a running centrifuge. Reasoning: do not open the lid immediately - aerosols may be present. Stop the run, leave the lid closed for 30 minutes, don gloves, gown and eye protection, remove glass with forceps, absorb and disinfect with 1:10 bleach for 10 minutes, discard as biomedical waste, then document and report the incident.
Traps that cost marks
- Recapping needles or filling sharps containers past the line.
- Using alcohol on a large blood spill (it fixes protein and evaporates too quickly).
- Mixing bleach too weak or too strong.
- Doffing PPE in the wrong order, or forgetting hand hygiene after removal.