HT Safety & Chemical Hazards 2 — Questions and Answers
Question 1: Which GHS pictogram indicates a chemical that is an acute toxin (fatal or toxic if swallowed, inhaled, or absorbed through skin)?
- Skull and crossbones (Correct answer)
- Exclamation mark
- Health hazard
- Flame over circle
Correct answer: Skull and crossbones
The skull and crossbones GHS pictogram designates chemicals with acute toxicity at categories 1–3.
Question 2: When working with osmium tetroxide in the histology lab, which personal protective equipment is MOST critical beyond gloves and a lab coat?
- Respiratory protection and chemical splash goggles (Correct answer)
- Hearing protection
- Steel-toed boots
- UV-protective glasses
Correct answer: Respiratory protection and chemical splash goggles
Osmium tetroxide vapors are extremely toxic and can permanently damage corneas, making respiratory protection and splash goggles essential.
Question 3: Under OSHA's Hazard Communication Standard, what is the minimum number of sections required in a Safety Data Sheet (SDS)?
- 16 (Correct answer)
- 10
- 12
- 8
Correct answer: 16
OSHA's HazCom 2012 standard, aligned with GHS, mandates a standardized 16-section SDS format.
Question 4: A histotechnician notices a sweet, fruity odor in the lab. This odor is MOST likely associated with which solvent?
- Xylene
- Formalin
- Acetone (Correct answer)
- Isopropyl alcohol
Correct answer: Acetone
Acetone has a characteristic sweet, fruity odor and is commonly used in histology as a fixative and solvent.
Question 5: Which class of fire extinguisher is appropriate for a flammable solvent (e.g., xylene) fire in the histology lab?
- Class B (Correct answer)
- Class A
- Class C
- Class D
Correct answer: Class B
Class B extinguishers are rated for flammable liquid fires, which include organic solvents like xylene and alcohols.
Question 6: The permissible exposure limit (PEL) for formaldehyde set by OSHA is:
- 0.75 ppm as an 8-hour TWA (Correct answer)
- 2.0 ppm as an 8-hour TWA
- 5.0 ppm as an 8-hour TWA
- 0.1 ppm as an 8-hour TWA
Correct answer: 0.75 ppm as an 8-hour TWA
OSHA's formaldehyde standard (29 CFR 1910.1048) sets the PEL at 0.75 ppm as an 8-hour time-weighted average.
Question 7: Which disposal method is correct for xylene-contaminated waste in a histology lab?
- Collect in labeled hazardous waste containers for licensed disposal (Correct answer)
- Dilute with water and pour down the drain
- Evaporate in the fume hood
- Mix with formalin waste for combined disposal
Correct answer: Collect in labeled hazardous waste containers for licensed disposal
Xylene is a regulated hazardous waste and must be segregated in labeled containers for licensed hazardous waste disposal.
HT Safety & Chemical Hazards 2
Which GHS pictogram indicates a chemical that is an acute toxin (fatal or toxic if swallowed, inhaled, or absorbed through skin)?