Laboratory Safety and Infection Control
Chemical and biological hazards
Histology labs combine chemical and biological risk. Formalin is a known carcinogen and irritant; xylene is flammable and neurotoxic; both require ventilation (fume hoods), proper labeling, and spill procedures. Candidates must know standard precautions: treat all specimens as potentially infectious, use personal protective equipment (gloves, gown, eye protection), and never mouth pipette.
Waste and disposal
Formalin and xylene are hazardous wastes and must not go down the drain; they are collected and disposed of per regulations. Sharps (blades, needles) go in puncture-resistant containers.
Exposure response
Know the basics: skin contact with formalin requires flushing with water; eye splash requires irrigation and medical evaluation; needlestick requires reporting and follow-up.
Traps
Questions often test the distinction between standard precautions and transmission-based precautions, or ask which waste stream a chemical belongs to. A frequent trap is assuming gloves replace hand hygiene, or that a fume hood is optional for xylene. Another is confusing a chemical spill kit with a biological spill kit.
Worked rule
If a question describes an unlabeled container of clear liquid near the processor, treat it as an unknown hazard: do not smell or taste; label, ventilate, and consult safety data sheets before handling.