CHST CHST - Construction Health and Safety Technician Hazardous Materials and Chemical Safety Questions and Answers 5 — Questions and Answers
Question 1: A construction site stores 500 gallons of diesel fuel in a single aboveground tank. Under EPA's Spill Prevention, Control, and Countermeasure (SPCC) rule, what is the MINIMUM secondary containment volume typically required?
- 10% of the tank's capacity
- 25% of the tank's capacity
- 110% of the tank's capacity (Correct answer)
- 150% of the tank's capacity
Correct answer: 110% of the tank's capacity
EPA's SPCC rule (40 CFR Part 112) generally requires secondary containment capable of holding 110% of the volume of the largest single tank to contain a full spill plus precipitation.
Question 2: Which exposure route is MOST significant for lead exposure on construction sites involving lead-based paint removal?
- Dermal absorption through intact skin
- Ingestion via hand-to-mouth contact (Correct answer)
- Injection through puncture wounds
- Eye contact with lead dust
Correct answer: Ingestion via hand-to-mouth contact
On construction sites, lead ingestion through hand-to-mouth contact (e.g., eating, drinking, or smoking without washing hands) is the primary route of entry for lead dust and fume particles.
Question 3: Under OSHA 29 CFR 1926.65 (HAZWOPER), workers performing hazardous waste site clean-up operations must receive how many hours of initial training before working on-site unsupervised?
- 8 hours
- 16 hours
- 24 hours
- 40 hours (Correct answer)
Correct answer: 40 hours
OSHA's HAZWOPER standard at 29 CFR 1926.65(e)(3) requires a minimum of 40 hours of off-site training plus 3 days of supervised field experience for general site workers.
Question 4: When using a chemical that has a flash point of 73°F (23°C) and a boiling point above 95°F (35°C), it is classified as a:
- Combustible liquid (Class II)
- Flammable liquid (Category 1)
- Flammable liquid (Category 2) (Correct answer)
- Non-flammable solvent
Correct answer: Flammable liquid (Category 2)
Under GHS/HazCom 2012, a flammable liquid with a flash point ≥23°C and ≤60°C and a boiling point >35°C is classified as Category 2 flammable liquid.
Question 5: A CHST notices workers using spray-applied coatings containing silica in an enclosed space without respiratory protection. The MOST appropriate corrective action is to:
- Post warning signs and allow work to continue until end of shift
- Stop work immediately, evacuate the space, and implement engineering controls and proper respiratory protection before resuming (Correct answer)
- Increase general ventilation by opening one additional door
- Provide half-face respirators with N95 filters to all workers and allow work to resume
Correct answer: Stop work immediately, evacuate the space, and implement engineering controls and proper respiratory protection before resuming
Respirable crystalline silica causes silicosis and lung cancer; OSHA's silica standard (29 CFR 1926.1153) requires immediate controls including stopping work if workers are exposed above the action level without protection.
Question 6: The GHS pictogram showing a skull and crossbones (☠) on a chemical label indicates:
- The chemical is an environmental hazard
- The chemical causes acute toxicity (fatal or toxic in small amounts) (Correct answer)
- The chemical is a skin sensitizer
- The chemical is a serious eye irritant
Correct answer: The chemical causes acute toxicity (fatal or toxic in small amounts)
The skull and crossbones GHS pictogram indicates acute toxicity categories 1–3, meaning the chemical can be fatal or toxic if inhaled, ingested, or absorbed through skin in small doses.
Question 7: When conducting a Job Hazard Analysis (JHA) for a task involving hydrogen sulfide (H₂S) in a confined space, which TWO characteristics of H₂S are MOST critical to note?
- It is heavier than air and has a very low IDLH (50 ppm) (Correct answer)
- It is lighter than air and has a high IDLH (500 ppm)
- It is detectable by smell at all dangerous concentrations
- It causes corrosion of metals but has no acute toxicity
Correct answer: It is heavier than air and has a very low IDLH (50 ppm)
H₂S is denser than air (accumulates in low areas of confined spaces) and has a very low IDLH of 50 ppm, making it immediately dangerous even at relatively low concentrations.
CHST CHST - Construction Health and Safety Technician Hazardous Materials and Chemical Safety Questions and Answers 5
A construction site stores 500 gallons of diesel fuel in a single aboveground tank.
Under EPA's Spill Prevention, Control, and Countermeasure (SPCC) rule, what is the MINIMUM secondary containment volume typically required?