HAZWOPER Hazard ID 5 — Questions and Answers
Question 1: During a HAZWOPER site survey, a worker detects a sweet, chloroform-like odor from an unlabeled drum. Which hazard class should be suspected first?
- Oxidizer
- Chlorinated solvent (halogenated hydrocarbon) (Correct answer)
- Explosive
- Reactive metal
Correct answer: Chlorinated solvent (halogenated hydrocarbon)
Sweet or chloroform-like odors are characteristic of chlorinated solvents such as TCE, PCE, or methylene chloride, which are common contaminants at industrial waste sites.
Question 2: Which instrument is MOST appropriate for detecting oxygen-deficient or oxygen-enriched atmospheres in a confined space at a HAZWOPER site?
- Photoionization detector (PID)
- Direct-reading colorimetric tube
- Multi-gas meter with electrochemical oxygen sensor (Correct answer)
- Flame ionization detector (FID)
Correct answer: Multi-gas meter with electrochemical oxygen sensor
Multi-gas meters equipped with electrochemical sensors specifically measure percent oxygen by volume and are required for confined space entry monitoring.
Question 3: What is the LOWER explosive limit (LEL) and why is it important for hazard identification?
- The highest concentration of vapor that will burn; above this the mixture is too rich to ignite
- The lowest concentration of vapor in air that will support combustion if ignited (Correct answer)
- The concentration at which vapors become toxic to inhale
- The temperature at which a liquid's vapor pressure equals atmospheric pressure
Correct answer: The lowest concentration of vapor in air that will support combustion if ignited
The LEL is the minimum flammable vapor concentration in air; below the LEL the mixture is too lean to ignite, making it a critical fire/explosion hazard benchmark.
Question 4: A site Safety Officer observes containers with corroded labels, bulging lids, and crystalline deposits around bungs. What HAZWOPER action is MOST appropriate?
- Open bungs to relieve pressure before moving the containers
- Treat containers as unknown hazards, isolate the area, and conduct air monitoring before proceeding (Correct answer)
- Move the containers to the waste storage area using standard lift equipment
- Apply neutralizing foam to the crystalline deposits immediately
Correct answer: Treat containers as unknown hazards, isolate the area, and conduct air monitoring before proceeding
Corroded labels, bulging containers, and crystalline deposits are signs of potential instability or pressure buildup, requiring isolation and characterization before any handling.
Question 5: Which GHS pictogram indicates an acute toxicity hazard (fatal or toxic if swallowed, inhaled, or absorbed through skin)?
- Flame over circle
- Skull and crossbones (Correct answer)
- Exclamation mark
- Health hazard (silhouette with starburst on chest)
Correct answer: Skull and crossbones
The skull and crossbones GHS pictogram indicates acute toxicity categories 1-3, representing the most severe immediate toxic hazards.
Question 6: What does a 'confined space' with an IDLH atmosphere require before any worker entry, per OSHA 1910.120?
- Only a buddy system with one person inside and one outside
- Continuous air monitoring, appropriate respiratory protection, and an attendant outside (Correct answer)
- Ventilation for at least 15 minutes followed by a single air reading
- Entry only if two or more qualified rescuers are immediately available on-site
Correct answer: Continuous air monitoring, appropriate respiratory protection, and an attendant outside
OSHA requires continuous atmospheric monitoring, appropriate PPE including respiratory protection, and a trained attendant stationed outside for IDLH confined space entry.
Question 7: Which of the following route-of-entry hazards is MOST relevant when working with fine powders or airborne dusts at a HAZWOPER site?
- Dermal absorption through intact skin
- Inhalation of respirable particles reaching the alveoli (Correct answer)
- Ingestion through direct contact with the mouth
- Injection through puncture wounds from sharp objects
Correct answer: Inhalation of respirable particles reaching the alveoli
Fine respirable particles (under 10 microns, especially under 4 microns) bypass upper respiratory defenses and reach the deep lung (alveoli), causing the greatest systemic exposure risk.
HAZWOPER Hazard ID 5
During a HAZWOPER site survey, a worker detects a sweet, chloroform-like odor from an unlabeled drum.
Which hazard class should be suspected first?