COHN Toxicology and Biohazards 5 — Questions and Answers
Question 1: A worker is splashed with an unknown corrosive chemical in the eyes. The IMMEDIATE first aid action is to:
- Apply a neutralizing solution specific to the pH of the chemical
- Cover both eyes with sterile dressings and transport to emergency care
- Irrigate both eyes continuously with water or saline for at least 15-20 minutes (Correct answer)
- Check the SDS before beginning any treatment to identify the chemical
Correct answer: Irrigate both eyes continuously with water or saline for at least 15-20 minutes
Immediate copious irrigation for 15-20 minutes takes priority over chemical identification because seconds count in preventing corneal damage — the SDS can be checked during or after irrigation.
Question 2: A toxicologist reports a chemical has a low therapeutic index. This means the chemical:
- Has a wide margin between effective and toxic doses
- Has a narrow margin between effective and toxic doses (Correct answer)
- Is excreted rapidly in urine without accumulation
- Crosses the blood-brain barrier more slowly than expected
Correct answer: Has a narrow margin between effective and toxic doses
A low therapeutic index (TI = LD50/ED50) means the effective dose and toxic dose are close together, leaving little margin for safety and requiring careful dosing.
Question 3: Universal precautions require that blood and body fluids from ALL patients be treated as:
- Potentially infectious regardless of known diagnosis (Correct answer)
- Infectious only if the patient tests positive for HIV or HBV
- Non-infectious unless visible blood contamination is present
- Infectious only in high-risk settings such as oncology or ICU units
Correct answer: Potentially infectious regardless of known diagnosis
Universal precautions, established by CDC, require treating all blood and specified body fluids as potentially infectious for bloodborne pathogens regardless of patient diagnosis or perceived risk.
Question 4: A worker in a beryllium machining facility develops progressive dyspnea and is found to have non-caseating granulomas on lung biopsy. The MOST likely diagnosis is:
- Silicosis
- Chronic beryllium disease (berylliosis) (Correct answer)
- Extrinsic allergic alveolitis (hypersensitivity pneumonitis)
- Sarcoidosis unrelated to occupational exposure
Correct answer: Chronic beryllium disease (berylliosis)
Chronic beryllium disease (CBD) is a granulomatous lung disease caused by beryllium sensitization; it is clinically and pathologically indistinguishable from sarcoidosis but requires beryllium lymphocyte proliferation test (BeLPT) for diagnosis.
Question 5: Which control measure represents the HIGHEST level of the hierarchy of controls for chemical hazards?
- Engineering controls such as local exhaust ventilation
- Administrative controls such as job rotation
- Personal protective equipment selection
- Elimination of the hazardous chemical from the process (Correct answer)
Correct answer: Elimination of the hazardous chemical from the process
Elimination (removing the hazard entirely) sits at the top of NIOSH's hierarchy of controls and is the most effective protective measure because it removes risk at the source.
Question 6: An agricultural worker presents with acute toxic effects after herbicide exposure. The MOST appropriate initial resource for identifying the chemical's acute health hazards and first aid measures is:
- Calling the state health department
- Reviewing the Safety Data Sheet (SDS) Section 4 (Correct answer)
- Consulting the worker's personal physician
- Ordering a complete metabolic panel
Correct answer: Reviewing the Safety Data Sheet (SDS) Section 4
SDS Section 4 (First Aid Measures) provides immediate, chemical-specific first aid instructions and is the most accessible reference for acute exposure management at the worksite.
Question 7: A COHN is developing a respiratory protection program. Under OSHA 29 CFR 1910.134, which step MUST occur before a worker is fit-tested for a respirator?
- Industrial hygiene air monitoring must show exposures above PEL
- The worker must complete a medical evaluation to determine fitness to wear a respirator (Correct answer)
- Engineering controls must be proven technologically infeasible
- The worker must select their own preferred respirator model
Correct answer: The worker must complete a medical evaluation to determine fitness to wear a respirator
OSHA's Respiratory Protection Standard requires a medical evaluation (using OSHA Medical Evaluation Questionnaire or equivalent) before fit testing to ensure the worker can safely wear respiratory protection.
COHN Toxicology and Biohazards 5
A worker is splashed with an unknown corrosive chemical in the eyes.
The IMMEDIATE first aid action is to: