ASP ASP Hazardous Materials and Chemical Safety 5 — Questions and Answers
Question 1: A worker is exposed to a chemical mixture containing two substances with additive effects. The combined exposure index (CEI) is calculated as:
- C1/TLV1 × C2/TLV2
- C1/TLV1 + C2/TLV2 (Correct answer)
- (C1+C2)/(TLV1+TLV2)
- Max(C1/TLV1, C2/TLV2)
Correct answer: C1/TLV1 + C2/TLV2
For additively acting chemicals, the combined exposure index is the sum of each component's concentration divided by its TLV; a sum >1 indicates overexposure.
Question 2: Which GHS pictogram indicates an acute toxicity hazard (oral, dermal, or inhalation)?
- Flame over circle
- Exclamation mark
- Skull and crossbones (Correct answer)
- Health hazard (exclamation in circle)
Correct answer: Skull and crossbones
The skull and crossbones pictogram is used for substances with severe acute toxicity (categories 1–3).
Question 3: Under RCRA, which characteristic makes a solid waste hazardous due to its potential to cause explosions or fire?
- Toxicity
- Corrosivity
- Reactivity
- Ignitability (Correct answer)
Correct answer: Ignitability
Ignitability is the RCRA characteristic applied to wastes that can readily catch fire, including flammable liquids with flash point <60°C.
Question 4: What does the term 'threshold limit value – short-term exposure limit' (TLV-STEL) represent?
- Maximum 8-hour time-weighted average concentration
- 15-minute concentration that should not be exceeded (Correct answer)
- Concentration immediately dangerous to life or health
- Annual average exposure concentration
Correct answer: 15-minute concentration that should not be exceeded
The TLV-STEL is the concentration to which workers can be exposed for up to 15 minutes without suffering irritation, chronic tissue damage, or narcosis.
Question 5: Which agency publishes the Emergency Response Guidebook (ERG) used by first responders at hazmat incidents?
- OSHA
- EPA
- NIOSH
- DOT/PHMSA (Correct answer)
Correct answer: DOT/PHMSA
The ERG is published by the US DOT's Pipeline and Hazardous Materials Safety Administration (PHMSA) in cooperation with Transport Canada and Mexico's SCT.
Question 6: A chemical's boiling point is 35°C (95°F). What is the primary hazard concern at room temperature (25°C)?
- Low vapor pressure generating minimal vapors
- High volatility producing significant vapor concentrations (Correct answer)
- Solid state creating dust explosion hazard
- Spontaneous combustion below ambient temperature
Correct answer: High volatility producing significant vapor concentrations
A boiling point near or below ambient temperature means the liquid will rapidly volatilize, generating high vapor concentrations that pose inhalation and flammability risks.
Question 7: Which containment method is most appropriate as the FIRST action when a small quantity of a corrosive liquid spills on a laboratory floor?
- Neutralize immediately with a strong base or acid
- Absorb with an appropriate inert material and contain the spill (Correct answer)
- Flush with large amounts of water directly into the drain
- Evacuate the building and call the fire department
Correct answer: Absorb with an appropriate inert material and contain the spill
Containing and absorbing the spill with inert absorbent material (e.g., vermiculite, dry sand) prevents spreading before neutralization or disposal.
ASP ASP Hazardous Materials and Chemical Safety 5
A worker is exposed to a chemical mixture containing two substances with additive effects.
The combined exposure index (CEI) is calculated as: