NHIE Environmental Concerns and Safety Issues 3 — Questions and Answers
Question 1: The EPA action level for radon in indoor air that triggers mitigation is:
- 2 pCi/L
- 4 pCi/L (Correct answer)
- 8 pCi/L
- 10 pCi/L
Correct answer: 4 pCi/L
The EPA recommends mitigation when long-term radon levels in a home reach or exceed 4 picocuries per liter of air.
Question 2: Which test method provides the most accurate long-term radon measurement for real estate transactions?
- Activated charcoal canister (short-term 48-hour test)
- Electret ion chamber (short-term)
- Alpha track detector deployed for 90+ days (Correct answer)
- Continuous electronic monitor for 24 hours
Correct answer: Alpha track detector deployed for 90+ days
Alpha track detectors used for 90 days or more provide the most accurate representation of long-term average radon exposure.
Question 3: A home inspector finds spray-applied fireproofing on structural steel beams in a 1960s building. The correct recommendation is:
- Remove all fireproofing immediately as it is asbestos
- Do not disturb the material and recommend sampling by a certified industrial hygienist (Correct answer)
- Seal the material with encapsulant paint
- Document the finding as non-hazardous because it is above occupied space
Correct answer: Do not disturb the material and recommend sampling by a certified industrial hygienist
Spray-applied fireproofing from that era is often asbestos-containing and must be sampled by a qualified professional before any determination or disturbance.
Question 4: Urea-formaldehyde foam insulation (UFFI) was banned for residential use in 1982 because of concerns about:
- Fire acceleration properties
- Formaldehyde off-gassing causing respiratory irritation and potential carcinogenicity (Correct answer)
- Water absorption leading to structural rot
- Incompatibility with electrical wiring insulation
Correct answer: Formaldehyde off-gassing causing respiratory irritation and potential carcinogenicity
The CPSC banned UFFI due to evidence that off-gassed formaldehyde caused eye and respiratory irritation and was a potential carcinogen.
Question 5: A home inspector detects a distinct rotten-egg odor near the water heater and gas lines. The most likely source is:
- Sulfur from corroded galvanized pipes releasing hydrogen sulfide into water supply
- Natural gas odorant (mercaptan) indicating a potential gas leak (Correct answer)
- Drain biofilm from P-traps evaporating through floor drains
- Hydrogen sulfide from a failing anode rod in the water heater
Correct answer: Natural gas odorant (mercaptan) indicating a potential gas leak
Natural gas is odorized with mercaptan (ethyl mercaptan) which has a strong rotten-egg smell, and its presence near gas equipment indicates a potential leak requiring immediate action.
Question 6: Which building material commonly found in pre-1978 homes is most likely to contain lead beyond paint?
- Fiberglass batt insulation
- Solder joints in copper supply plumbing (Correct answer)
- Cedar shake roofing
- Cellulose blow-in insulation
Correct answer: Solder joints in copper supply plumbing
Lead solder was widely used to join copper pipes in residential plumbing until it was banned for potable water systems in 1986.
Question 7: An inspector finds mold growth on the backside of drywall in an exterior wall cavity. The most likely contributing cause is:
- Excessive interior humidity condensing on the cooler wall surface (Correct answer)
- High exterior UV radiation breaking down the paper facing
- Inadequate grounding of electrical wiring
- Presence of lead paint on the exterior
Correct answer: Excessive interior humidity condensing on the cooler wall surface
Warm, moist interior air reaching a cool surface within the wall cavity can condense, providing moisture that supports mold growth on organic materials like drywall paper.
NHIE Environmental Concerns and Safety Issues 3
The EPA action level for radon in indoor air that triggers mitigation is: