Industrial Hygiene and Occupational Health practice questions

Answer: D) Binds to hemoglobin

• AIncorrect. It interferes with oxygen.
• BIncorrect. That's a simple asphyxiant.
• CIncorrect. It isn't corrosive.
• DCorrect. Blocking oxygen transport.

Answer: C) Threatens life or escape

• AIncorrect. It's life-threatening.
• BIncorrect. That's a TWA.
• CCorrect. Immediately dangerous to life or health.
• DIncorrect. It's for airborne hazards.

Answer: B) Hexavalent chromium formed from the base metal

Stainless steel contains chromium, so welding it creates hexavalent chromium, which OSHA identifies as a carcinogen. Controls such as local exhaust ventilation are needed. Zinc, cadmium and lead fumes come from coatings or other materials.

• AIncorrect. Zinc oxide fume, which can cause metal fume fever, comes mainly from welding galvanized (zinc-coated) steel, not stainless steel.
• BCorrect. OSHA says a major source of Cr(VI) exposure is hot work such as welding on stainless steel and other chromium-containing alloys, and that Cr(VI) is known to cause cancer.
• CIncorrect. Cadmium fume is a concern when welding or brazing cadmium-plated parts or using cadmium-bearing filler. It is not the defining hazard of stainless steel.
• DIncorrect. Lead fume comes mainly from hot work on lead-painted or lead-containing materials. It is not the characteristic hazard of stainless steel.

Answer: C) Half the permissible exposure limit

• AIncorrect. That's far higher.
• BIncorrect. That's above the limit.
• CCorrect. It triggers monitoring and other requirements.
• DIncorrect. Action levels trigger requirements.

Answer: A) No more than 20% of a normal exposure on day 1, increasing by no more than 20% on each later day

NIOSH recommends that new workers start at no more than 20% of a normal heat exposure on day 1 and add no more than 20% each day, usually over 7 to 14 days. The 50/60/80/100% schedule is meant for experienced workers.

• ACorrect. NIOSH recommends that new workers start at no more than 20% exposure on day 1 and increase by no more than 20% on each additional day. Full acclimatization usually takes about 7 to 14 days.
• BIncorrect. This shorter schedule is NIOSH's recommendation for experienced workers who already have prior heat exposure, not for new workers.
• CIncorrect. Water and rest breaks are important, but they don't replace gradually building up heat exposure. Full shifts from day 1 put unacclimatized workers at high risk of heat illness.
• DIncorrect. NIOSH calls for small daily increases, starting at no more than 20% on day 1, not a long fixed period followed by a sudden jump to full exposure.

Answer: D) Carbon monoxide from incomplete fuel combustion

Propane forklift exhaust contains carbon monoxide, which can build up to dangerous levels indoors. CDC reports describe CO poisoning tied to poorly maintained LPG forklifts and inadequate ventilation.

• AIncorrect. Hydrogen buildup is a concern where lead-acid batteries for electric forklifts are charged. It is not a byproduct of propane engine exhaust.
• BIncorrect. Diesel particulate comes from diesel-fueled engines. Propane burns much cleaner in terms of particulate, and particulate would not explain these symptoms.
• CIncorrect. Propane is odorized with a mercaptan in tiny amounts so leaks can be smelled. Engine operation does not produce hazardous hydrogen sulfide levels.
• DCorrect. LPG forklifts, especially poorly tuned ones, can emit very high CO concentrations. With inadequate ventilation, CO builds up and causes headache, dizziness and nausea. Controls include engine maintenance and tuning, ventilation and CO monitoring.

Answer: A) Continues or recurs over a long period, often more than a year

Chronic exposure means contact with a substance over a long time (CDC: typically more than one year). Acute exposure happens once or for a short time.

• ACorrect. CDC defines chronic exposure as contact with a substance that occurs for a long time, typically more than one year. Its effects may show up long after exposure begins.
• BIncorrect. CDC defines contact that occurs once or for a short time as acute exposure, not chronic.
• CIncorrect. Chronic refers to how long the exposure lasts, not how severe it is or how fast symptoms appear. Symptoms on the same day are typical of acute effects.
• DIncorrect. Any agent, chemical or physical, can be a chronic exposure. The term describes duration, not the type of agent.

Answer: A) They can damage hearing, and combined exposure with noise may cause greater-than-additive hearing loss

Ototoxic chemicals such as toluene and styrene can damage hearing, and many have a synergistic effect when combined with noise. Hearing conservation programs should account for them, even when noise is below regulatory limits.

• ACorrect. The OSHA/NIOSH bulletin says ototoxicants damage hearing and that many have a greater-than-additive (synergistic) effect on hearing loss when combined with noise.
• BIncorrect. The bulletin notes that some solvents may worsen hearing loss even when noise levels are below OSHA's permissible limits.
• CIncorrect. Ototoxicants can damage cochlear hair cells and nerve fibers, which causes lasting hearing loss. Audiometric testing should be considered for exposed workers.
• DIncorrect. Ototoxicity means damage to the ear (hearing or balance), not to the eye. Eye protection does nothing to reduce this hazard.

Answer: A) 0.1 fiber/cc as an 8-hour TWA

• ACorrect. There's also an excursion limit.
• BIncorrect. That's far too high.
• CIncorrect. That's lower than the PEL.
• DIncorrect. A PEL applies.

Answer: A) Biological monitoring of absorbed dose

Analyzing blood for lead (and ZPP) is biological monitoring. It shows the dose a worker actually absorbed from all routes, while air and wipe sampling measure lead in the environment.

• ACorrect. Measuring a substance or its effect marker in blood is biological monitoring. Blood lead reflects lead actually absorbed by all routes, including inhalation and ingestion, and OSHA's lead standard requires periodic blood lead and ZPP sampling.
• BIncorrect. Breathing-zone sampling measures the airborne lead concentration a worker would inhale without a respirator. It does not measure what the body actually absorbed.
• CIncorrect. Wipe sampling measures lead deposited on surfaces, which helps judge ingestion risk and housekeeping. It does not sample the worker's body.
• DIncorrect. Area sampling measures general airborne concentrations at fixed points in the workplace. It does not show any individual's absorbed dose.