CHST - Construction Health and Safety Technician Health Hazards and PPE Questions and Answers 5

Question 1

A CHST is evaluating a confined-space hot-work task in which a worker will weld galvanized steel inside a poorly ventilated tank. Which health hazard is MOST specific to this exposure, and which respiratory protection approach is most appropriate if engineering controls cannot reduce exposure below the PEL?

Accepted Answer

Metal fume fever from zinc oxide; a supplied-air respirator or other atmosphere-supplying respirator, because the space may also be oxygen-deficient

Answer

Welding galvanized (zinc-coated) steel produces zinc oxide fume, which causes metal fume fever. In a poorly ventilated tank, oxygen deficiency and other contaminants are also possible, so an atmosphere-supplying respirator (supplied-air or SCBA) is the appropriate choice. Air-purifying respirators do not protect in oxygen-deficient atmospheres, and organic vapor cartridges or N95s are not designed for welding fume in a confined space.

Question 2

A fit test is being conducted for a worker who must wear a tight-fitting negative-pressure half-mask respirator. The worker has a full beard that lies along the sealing surface. What is the correct action under OSHA's respiratory protection standard?

Accepted Answer

Do not permit the worker to wear the tight-fitting respirator; use a loose-fitting powered air-purifying respirator hood or require the worker to be clean shaven

Answer

OSHA 29 CFR 1910.134(g)(1) prohibits tight-fitting respirators for workers with facial hair that comes between the sealing surface and the face or interferes with valve function. Fit testing cannot be used to get around this. Acceptable options include shaving or using a loose-fitting facepiece such as a PAPR hood or helmet, which does not rely on a face seal.

Question 3

During an overhead demolition task, a worker is exposed to respirable crystalline silica at 3 times the OSHA PEL of 50 µg/m³ as an 8-hour TWA (measured at 150 µg/m³). Using the assigned protection factors, which respirator is the MINIMUM acceptable choice?

Accepted Answer

A half-mask air-purifying respirator with P100 filters (APF 10)

Answer

The exposure is 3 times the PEL, so the required APF is at least 3, and the respirator must also be NIOSH-approved with a particulate filter. A half-mask APR with P100 filters has an APF of 10, which is sufficient (maximum use concentration is 10 × 50 = 500 µg/m³). Note that an N95 filtering facepiece also has an APF of 10 and would provide the numeric protection, but the question asks for the minimum acceptable among the options and the N95-only choice is worded as limited; the P100 half-mask is the standard acceptable selection that satisfies the required APF with a higher-efficiency filter. The loose-fitting PAPR exceeds the minimum, and hearing protection is irrelevant to silica.

Question 4

A CHST is selecting gloves for a crew handling a two-part epoxy resin system that includes aromatic amine hardeners and solvents. Which statement reflects the BEST glove selection practice?

Accepted Answer

Select gloves based on the manufacturer's permeation and breakthrough time data for the specific chemicals and the SDS, often a laminate film or butyl option rather than thin disposable gloves

Answer

Glove materials have different breakthrough times and permeation rates for each chemical. Epoxy components, amines, and solvents can permeate thin nitrile or latex quickly. The best practice is to consult the SDS and the manufacturer's chemical resistance data and choose a material, such as laminate film, butyl, or a thicker chemical-rated glove, with adequate breakthrough time for the duration of the task. Absorbent cotton increases skin contact.

Question 5

A noise survey shows a worker's 8-hour time-weighted average exposure is 92 dBA. The employer has a hearing conservation program with a hearing protector rated at an NRR of 25. Using OSHA's method for estimating the protected exposure when only A-weighted measurements are available, what is the estimated TWA at the ear, and is it adequate?

Accepted Answer

92 − (25 − 7) = 74 dBA; adequate

Answer

Under OSHA's Appendix B method, when noise is measured in dBA the NRR must be reduced by 7 dB (the C-to-A conversion): 25 − 7 = 18 dB. The estimated protected exposure is 92 − 18 = 74 dBA, which is below the 85 dBA action level and adequate. The 50 percent derating is an NIOSH practice and not the OSHA method for dBA measurements; the 7 dB correction is applied instead.

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Practice Test

CHST - Construction Health and Safety Technician Health Hazards and PPE Questions and Answers 5