Chemical Hazard & Risk Management Flashcards

A Marine Chemist is assessing a tank that transported a sensitizer chemical. Beyond flammability and acute toxicity, which long-term health risk must be specifically evaluated in the re-entry risk assessment?

Answer: Potential for allergic sensitization in workers, where even sub-TLV concentrations may trigger severe reactions in previously sensitized individuals

Sensitizers require special consideration because previously sensitized workers may react severely at concentrations well below the established TLV, necessitating stricter exposure controls.

The concept of 'inherently safer design' applied to a vessel's chemical handling system would best be exemplified by:

Answer: Redesigning cargo piping to reduce inventory of hazardous material held in lines during transfer

Inherently safer design reduces hazard by minimizing the quantity of hazardous material present (minimization), rather than relying on added controls or warnings.

During a pre-entry evaluation, a Marine Chemist detects carbon monoxide at 35 ppm in an engine room bilge space. The OSHA PEL for CO is 50 ppm TWA. What is the appropriate response?

Answer: Identify and eliminate the CO source before authorizing entry, as 35 ppm indicates active generation that could increase rapidly

A CO reading of 35 ppm indicates an active source; sources in enclosed spaces can escalate rapidly, and the root cause must be identified and controlled before entry is authorized.

Which of the following correctly describes the difference between a 'hazard' and a 'risk' in chemical safety terminology used by a Marine Chemist?

Answer: Hazard is the inherent potential of a chemical to cause harm; risk is the likelihood and severity of harm occurring under specific conditions of exposure

Hazard is an intrinsic property of the chemical, while risk accounts for the probability and magnitude of harm under actual exposure conditions.

A Marine Chemist is asked to evaluate suitability for entry into a tank that contained a polymerizable monomer (e.g., styrene). Which specific hazard unique to polymerizable materials must be assessed?

Answer: Runaway exothermic polymerization if the inhibitor has depleted, generating heat and toxic vapors

Polymerizable monomers are stabilized with inhibitors that can deplete over time; without inhibitor, spontaneous exothermic polymerization can release toxic vapors and create a thermal runaway hazard.

Under 29 CFR 1915.12, an 'immediately dangerous to life or health' atmosphere requires which type of respiratory protection for entry?

Answer: Pressure-demand self-contained breathing apparatus (SCBA) or pressure-demand supplied-air respirator with emergency egress SCBA

IDLH atmospheres require pressure-demand SCBA or pressure-demand SAR with escape SCBA because these provide the highest assigned protection factors and positive pressure prevents inward leakage.

A Marine Chemist conducting a risk assessment uses the formula: Risk = Consequence × Probability. If the consequence of a chlorine release is rated 'catastrophic' (5) and probability is 'unlikely' (2), the risk score is 10. How does this score typically guide decision-making?

Answer: The score is compared to a risk tolerance matrix to determine whether additional controls are needed to reduce consequence, probability, or both

Risk scores are referenced against a pre-established tolerance matrix; a score of 10 may fall in an 'as low as reasonably practicable' zone requiring evaluation of mitigation options rather than automatic shutdown.