Emergency Response to Hazardous Releases practice questions for the CHST exam
CHST5 Domain 2: Emergency Preparedness, Incident Investigation, and Response (K2.3 Environmental contamination response; K2.4 Incident command; K2.6 Response equipment). 3 free questions below. Every answer quotes and links the regulation paragraph it rests on.
- 29 CFR 1910.120: Hazardous waste operations and emergency response. · how this section is tested
Text pulled from the eCFR, current as of 2026-10-14.
A chemical tank at a construction staging yard begins leaking onto the ground. The site's designated first responders at the operations level arrive and are expected to act as part of the initial response. Which action is consistent with their role?
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Answer: C. Contain the release from a safe distance and keep it from spreading
Operations-level responders respond defensively, containing the release from a safe distance, keeping it from spreading and preventing exposures. Plugging or patching at the point of release is the more aggressive role of a hazardous materials technician, so it is wrong for this level.
“They are trained to respond in a defensive fashion without actually trying to stop the release. Their function is to contain the release from a safe distance, keep it from spreading, and prevent exposures.”
A contractor's crew could face a chemical release while excavating at a former industrial site. Management plans to have all workers evacuate immediately if a release occurs, and no employee will be allowed to help handle the emergency. Which statement correctly describes the contractor's obligation under the emergency response requirements?
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Answer: D. The contractor is exempt from the full emergency response plan requirement if it provides an emergency action plan in accordance with 29 CFR 1910.38.
The standard exempts employers who evacuate employees from the danger area and permit none of them to assist in handling the emergency, provided they have an emergency action plan under 1910.38. A full plan is not required for them, and no fire department agreement or incident commander training is required for the exemption.
“Employers who will evacuate their employees from the danger area when an emergency occurs, and who do not permit any of their employees to assist in handling the emergency, are exempt from the requirements of this paragraph if they provide an emergency action plan in accordance with 29 CFR 1910.38.”
Responders at a tank car leak of a volatile toxic liquid are wearing positive-pressure SCBA. After an hour the leak has been stopped, and a crew leader reports that no odor is noticeable. The crew leader asks to switch the team to lighter air-purifying respirators to reduce fatigue. Under the standard, what must happen before the respiratory protection can be reduced?
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Answer: C. The individual in charge of the ICS must determine through air monitoring that a decreased level of protection will not result in hazardous exposures.
The standard requires positive pressure SCBA until the individual in charge of the ICS decides, based on air monitoring, that less protection will not cause hazardous exposures. Odor, a stopped leak, and elapsed time are not monitoring results, so none of them can justify the downgrade.
“Employees engaged in emergency response and exposed to hazardous substances presenting an inhalation hazard or potential inhalation hazard shall wear positive pressure self-contained breathing apparatus while engaged in emergency response, until such time that the individual in charge of the ICS determines through the use of air monitoring that a decreased level of respiratory protection will not result in hazardous exposures to employees.”
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Original practice questions, not real exam items. PassCited is not affiliated with or endorsed by BCSP.