COHN Toxicology and Biohazards 3

Question 1

Which route of exposure is the MOST common pathway for occupational chemical poisoning?

Accepted Answer

Inhalation

Answer

Inhalation is the most common occupational exposure route because workers breathe contaminated air continuously, providing direct access to the large surface area of the lungs.

Question 2

A healthcare worker receives a needlestick injury from a patient with unknown HIV status. According to CDC guidelines, post-exposure prophylaxis (PEP) should be initiated within:

Accepted Answer

72 hours

Answer

CDC guidelines recommend initiating HIV PEP as soon as possible, ideally within hours of exposure, but no later than 72 hours for maximum effectiveness.

Question 3

Hydrogen sulfide (H₂S) is particularly dangerous because at high concentrations it:

Accepted Answer

Paralyzes the olfactory nerve, eliminating the warning odor

Answer

At high concentrations, H₂S rapidly paralyzes the olfactory nerve so workers lose the rotten-egg warning odor and can be overcome without realizing the danger.

Question 4

The concept of 'skin notation' (Sk) on a chemical's TLV indicates that:

Accepted Answer

Significant absorption through intact skin can contribute to total body burden

Answer

Skin notation alerts occupational health professionals that dermal absorption of the chemical can be significant enough to add to systemic toxicity, even when air levels are controlled.

Question 5

A construction worker is found unconscious in a confined space where fuel combustion equipment was used. The FIRST priority action is:

Accepted Answer

Put on supplied-air SCBA before entering to rescue

Answer

Confined space rescuers must use supplied-air SCBA because entering without respiratory protection leads to multiple fatalities — the majority of confined space deaths are untrained would-be rescuers.

COHN Exam Practice Test

COHN Exam Practice Test

COHN Toxicology and Biohazards 3