CHST study guide on the current CHST5 blueprint

A propane hose leaks in a basement where finishers are working. Where is the flammable vapor MOST likely to accumulate?

Pick the option you would mark on test day. The choice stays fixed, and every option then explains itself.

1. At the ceiling near the light fixtures

   Collecting at the ceiling describes lighter-than-air gases such as natural gas (methane); propane behaves the opposite way.
2. Near the floor and in low spots

   Propane vapor is about one and a half times as heavy as air, so it flows down and pools in floor drains, pits and low corners of the basement.
3. Around the leaking hose fitting

   Vapor does not stay around the leaking hose fitting; in an enclosed basement it keeps spreading along the floor far beyond the hose.
4. Evenly mixed throughout the room

   A heavy vapor released into still air settles instead of mixing evenly, which is why low spots can reach the flammable range while breathing-height readings look clean.

A technician runs nuclear density gauge tests on compacted subgrade while laborers work nearby. Which practice BEST keeps the laborers' radiation exposure as low as reasonably achievable (ALARA)?

1. Store the gauge in the truck cab between tests

   The cab is where the crew sits, so keeping the gauge there puts a radioactive source next to people; it belongs locked in its case and secured away from occupied space.
2. Keep others back while the rod is extended

   With the source rod extended the gauge gives off the most radiation, so keeping bystanders back during each reading applies distance, one of the three ALARA tools along with time and shielding.
3. Leave the rod extended between nearby tests

   Carrying the gauge between spots with the source exposed adds needless exposure time; the rod goes back to the safe position after each test.
4. Badge the laborers instead of moving them

   Badging the laborers only records dose after it is received; it lowers nobody's exposure, so it cannot stand in for moving people away.

A flagger who has stood still for hours on a hot day becomes light-headed and briefly faints, then recovers quickly and is alert. Which response fits NIOSH guidance?

1. Give salt tablets and keep the flagger standing

   Salt tablets are not advised for heat illness, and staying upright is exactly what lets blood pool in the legs and bring on fainting.
2. Return to flagging after a short rest

   A short rest followed by a return to flagging in the sun recreates the conditions that caused the faint, without cooling or fluids first.
3. Sit or lie in a cool place and sip water

   A brief faint after standing for hours in heat is heat syncope, and NIOSH advises sitting or lying down in a cool place and slowly drinking water or a sports drink.
4. Begin ice-water immersion right away

   Cold-water immersion treats heat stroke, where the person is confused or unresponsive with a very high body temperature; this flagger is alert and recovering.

A site's electric evacuation siren will be out of service for two days while its controller is replaced. What do OSHA's employee alarm rules (1910.165, adopted for construction by 1926.159) require during the outage?

1. A posted notice that the siren is down

   A posted notice tells people the siren is down but gives them no way to learn of an emergency, so it does not meet the backup requirement.
2. A backup means such as runners or phones

   Whenever an employee alarm system is out of service, the rule requires a backup way to alert workers, such as runners or telephones.
3. A log entry noting the outage dates

   A log entry noting the outage dates records the problem but alerts no one in an emergency; the backup means is required for as long as the system is down.
4. Stopping work until it is repaired

   Stopping work goes beyond the requirement; work can continue once an alternate way of sounding the alarm is in place.

A contractor wants its own responders to approach a leaking chlorine cylinder and cap the valve to stop the release. What is the minimum HAZWOPER training level for this task?

1. Hazmat technician, 24 hours

   Approaching a leaking cylinder to cap the valve is offensive action, which HAZWOPER reserves for hazardous materials technicians with at least 24 hours of operations-level training plus technician competencies.
2. 40-hour site cleanup worker training

   The 40-hour course covers workers at hazardous waste cleanup sites, a different part of HAZWOPER from emergency response to a release.
3. First responder awareness level

   Awareness-level responders recognize a release and call for help, and take no further action.
4. First responder operations, 8 hours

   Operations-level responders act defensively from a safe distance, for example by diking or diverting a release; they are not trained to stop it at the source.

A contractor forms an in-house hazardous materials response team. Besides training, what does HAZWOPER require for the team members?

1. A single physical when hired

   A single physical when hired misses changes over time and follow-up after a response exposure, both of which surveillance covers.
2. A hazmat endorsement on each license

   A hazmat endorsement is a commercial driver's license credential for hauling hazardous materials and has nothing to do with response team members.
3. A current CPR card for each member

   A CPR card for each member is not what HAZWOPER asks of a hazmat team; the medical requirement is a baseline exam plus ongoing surveillance.
4. A medical surveillance program

   Hazmat team members need a baseline physical and ongoing medical surveillance, because entry PPE and chemical exposure put real strain on the body.

A laborer servicing a portable toilet gets a needlestick from a used syringe contaminated with another person's blood. When the case is entered on the OSHA 300 Log, what must the employer do?

1. Enter 'privacy case' in place of the name

   A needlestick contaminated with another person's blood is a listed privacy concern case, so the employer writes 'privacy case' in the name column and keeps a separate confidential list of names.
2. Enter the name unless the laborer objects

   A contaminated needlestick is a privacy case without any request, so the name stays off the log whether or not the laborer objects.
3. Enter the name; needlesticks are not privacy cases

   This reverses the rule: contaminated sharps injuries are on the short list of cases entered without the worker's name.
4. Leave the case off the log for privacy

   Privacy protection hides the name, not the case; the needlestick still has to be recorded.

A contractor wants a consensus standard that sets out the elements of a comprehensive managed fall protection program, including policy, duties, training, rescue and program evaluation. Which standard addresses this?

1. ANSI/ASSP Z490.1

   Z490.1 sets accepted practices for safety, health and environmental training in general, only one piece of a fall program.
2. ANSI/ASSP Z10

   Z10 describes a general occupational health and safety management system for all hazards; it does not set the fall-specific elements such as rescue planning.
3. ANSI/ASSP Z359.2

   Z359.2 sets the minimum requirements for a comprehensive managed fall protection program, covering policy, duties, training, rescue procedures and program evaluation.
4. ANSI/ASSP Z359.14

   Z359.14 is a product standard for self-retracting devices, not a standard for running a program.

On a U.S. Army Corps of Engineers construction contract, which document must the contractor prepare for each definable feature of work under EM 385-1-1?

1. A Process Safety Management plan

   PSM applies to processes holding highly hazardous chemicals above threshold quantities, not to each feature of a construction contract.
2. An OSHA 300A annual summary

   The 300A totals a year's recordable cases for posting; it is a recordkeeping form, not a plan for a phase of work.
3. An Activity Hazard Analysis

   EM 385-1-1 requires an AHA for each definable feature of work, listing its steps, hazards, controls and the competent or qualified people, accepted before that work begins.
4. A NIOSH Health Hazard Evaluation

   A Health Hazard Evaluation is a NIOSH study requested for a workplace, not a document a contractor prepares for each work phase.

Foremen tell the superintendent only what they think he wants to hear, leaving out hazards and delays, so he learns of problems late. Which communication barrier is this?

1. Information overload

   Information overload means a receiver swamped by too many messages; here the superintendent gets too little information, not too much.
2. Physical noise

   Physical noise is interference such as engine sound or a weak radio link; nothing in the scenario blocks the message physically.
3. Jargon

   Jargon is technical language the receiver cannot follow; the foremen's reports are easy to understand, just incomplete.
4. Filtering

   Passing upward only what the superintendent is expected to like, and leaving out hazards and delays, is filtering: the sender shapes the message so it looks more favorable.

A revised fall protection plan has been issued, but old copies remain in several crews' gang boxes. What is the BEST action?

1. Pull the old copies and brief workers on changes

   Document control means obsolete versions come out of the point of use and the people who follow the plan are told what changed; both halves close the gap.
2. Stamp the old copies 'superseded' and leave them

   Stamping keeps an obsolete plan at the point of use and still tells no one what the revision changed.
3. Email the new version to the foremen

   An email to the foremen leaves the old copies where they are and assumes every change reaches the workers who use the plan.
4. Leave the old copies in the gang boxes

   Crews reach for the paper in their gang box, not the server, so leaving outdated copies there invites work to an obsolete plan.

A laborer stops a concrete pour because a wall form looks like it is bulging. The form turns out to be sound, and the PM is irritated by the 40-minute delay. Which response MOST strengthens stop-work authority?

1. Review the stop with the PM before thanking anyone

   Holding the thanks until an irritated PM weighs in puts the stop on trial and delays the message the crews need.
2. Ask crews to confirm a hazard before stopping

   Asking crews to confirm a hazard before stopping defeats the purpose; workers rarely know for sure, and the stop is how the doubt gets checked.
3. Thank the laborer privately but note the delay's cost

   Adding the cost of the delay turns thanks into a warning and teaches workers that a stop will be held against them.
4. Thank the laborer publicly for the good-faith stop

   Recognizing a good-faith stop in front of others, even one that proved unnecessary, shows every crew that stopping is expected and safe.