NSC Chemical Safety 4 — Questions and Answers
Question 1: Which of the following best describes a 'threshold limit value' (TLV) for airborne chemicals?
- A legally enforceable OSHA exposure limit
- An ACGIH recommended guideline for airborne concentration levels (Correct answer)
- The minimum detectable concentration of a chemical
- The concentration at which a chemical becomes visible as a vapor
Correct answer: An ACGIH recommended guideline for airborne concentration levels
TLVs are advisory occupational exposure guidelines published by ACGIH (American Conference of Governmental Industrial Hygienists), not legally enforceable limits.
Question 2: What is the correct method for disposing of a small amount of used solvent-soaked rags in the workplace?
- Place them in the regular trash
- Store them loosely in an open container
- Place them in a self-closing, approved flammable waste container (Correct answer)
- Rinse them in a sink and hang to dry
Correct answer: Place them in a self-closing, approved flammable waste container
Solvent-soaked rags must be stored in self-closing, approved flammable waste containers to prevent spontaneous combustion and fire hazards.
Question 3: A corrosive chemical is one that:
- Burns through metal containers rapidly
- Destroys living tissue or degrades materials on contact (Correct answer)
- Reacts violently with water
- Produces flammable vapors at room temperature
Correct answer: Destroys living tissue or degrades materials on contact
Corrosive chemicals cause destruction of living tissue (skin, eyes, mucous membranes) or material degradation on contact.
Question 4: When is it acceptable to eat, drink, or apply cosmetics in an area where hazardous chemicals are used?
- If gloves are worn
- After washing hands but while still in the work area
- Only during designated break times away from the chemical area (Correct answer)
- Never, unless no food-contact chemicals are present
Correct answer: Only during designated break times away from the chemical area
Eating, drinking, and applying cosmetics should only occur in designated areas away from hazardous chemical zones to prevent accidental ingestion of contaminants.
Question 5: What does a Hazardous Materials Information System (HMIS) rating of '3' in the health category mean?
- Slight health hazard — minor irritation possible
- Serious health hazard — major injury possible with short-term exposure (Correct answer)
- Severe health hazard — life-threatening with short-term exposure
- Minimal hazard — no significant risk
Correct answer: Serious health hazard — major injury possible with short-term exposure
An HMIS health rating of 3 indicates a serious hazard where short-term exposure could cause serious, temporary or moderate residual injury.
Question 6: Which engineering control is most effective at reducing worker exposure to airborne chemical hazards?
- Administrative controls such as job rotation
- Respiratory protective equipment
- Local exhaust ventilation (LEV) at the source (Correct answer)
- Posting warning signs near the hazard
Correct answer: Local exhaust ventilation (LEV) at the source
Local exhaust ventilation captures and removes chemical contaminants at the source before they disperse into the worker's breathing zone.
Question 7: What information is required on every container of a hazardous chemical in the workplace under HazCom?
- Chemical formula, CAS number, and expiration date
- Product identifier, hazard pictograms, signal word, and hazard statements (Correct answer)
- Supplier's phone number, price per unit, and storage code
- Employee signature, date received, and quantity used
Correct answer: Product identifier, hazard pictograms, signal word, and hazard statements
OSHA's HazCom standard requires labels to include a product identifier, GHS pictograms, signal word, hazard statements, precautionary statements, and supplier information.
NSC Chemical Safety 4
Which of the following best describes a 'threshold limit value' (TLV) for airborne chemicals?