HT Safety & Chemical Hazards 3 — Questions and Answers
Question 1: Which chemical hazard does mercury-containing compounds (e.g., B-5 fixative) primarily pose?
- Heavy metal toxicity with strict waste disposal requirements (Correct answer)
- Explosive risk at room temperature
- Strong oxidizer that can ignite combustibles
- Highly corrosive to skin on brief contact
Correct answer: Heavy metal toxicity with strict waste disposal requirements
Mercury-based fixatives pose heavy metal toxicity risks and generate regulated hazardous waste requiring special disposal procedures.
Question 2: An employee experiences skin sensitization after repeated xylene exposure. According to GHS, xylene's skin sensitization hazard is indicated by which pictogram?
- Exclamation mark (Correct answer)
- Health hazard
- Skull and crossbones
- Corrosion
Correct answer: Exclamation mark
The GHS exclamation mark pictogram covers skin sensitizers (category 1), irritants, and acute toxicity category 4 chemicals.
Question 3: When a large formaldehyde spill occurs in the grossing area, what is the FIRST action the histotechnician should take?
- Evacuate the area and alert others (Correct answer)
- Begin mopping with paper towels immediately
- Apply neutralizing agent directly to the spill
- Continue working and increase ventilation
Correct answer: Evacuate the area and alert others
Evacuating and alerting others limits additional exposure and ensures the spill is handled by trained personnel with appropriate PPE.
Question 4: Chromic acid (used in some histology procedures) is classified as which type of hazard?
- Oxidizer and corrosive (Correct answer)
- Flammable and explosive
- Acutely toxic by inhalation only
- Cryogenic liquid
Correct answer: Oxidizer and corrosive
Chromic acid is a strong oxidizer and corrosive that can ignite organic materials on contact and cause severe chemical burns.
Question 5: According to NFPA 704 (fire diamond), a blue quadrant rating of '3' indicates:
- Serious health hazard — short exposure could cause serious injury (Correct answer)
- Extreme health hazard — short exposure could cause death
- Moderate health hazard
- No health hazard
Correct answer: Serious health hazard — short exposure could cause serious injury
NFPA 704 blue quadrant rating 3 means short-term exposure could cause serious temporary or residual injury.
Question 6: Which ventilation system is specifically required by OSHA when handling formaldehyde above the action level?
- Local exhaust ventilation (LEV) at the point of use (Correct answer)
- General dilution ventilation throughout the building
- Positive-pressure room ventilation
- Recirculating HEPA filtration only
Correct answer: Local exhaust ventilation (LEV) at the point of use
OSHA's formaldehyde standard requires local exhaust ventilation to capture vapors at the source before they reach the worker's breathing zone.
Question 7: Picric acid (trinitrophenol) used in Bouin's fixative is particularly hazardous because dry picric acid is:
- Shock-sensitive and explosive (Correct answer)
- A strong respiratory sensitizer
- Carcinogenic by IARC Group 1 classification
- Highly corrosive to stainless steel containers
Correct answer: Shock-sensitive and explosive
Dry picric acid is shock-sensitive and can detonate; it must be kept moist and stored away from metals that form explosive picrate salts.
HT Safety & Chemical Hazards 3
Which chemical hazard does mercury-containing compounds (e.g., B-5 fixative) primarily pose?