Practice Test Geeks(CMC) Certified Marine Chemist Practice Test
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Chemical Hazard & Risk Management Flashcards

7 cards from real CMC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Chemical Hazard & Risk Management flashcards as text

  1. A confined space entry permit lists benzene as a contaminant at 4 ppm. The OSHA PEL-TWA for benzene is 1 ppm. What is the correct action before authorizing entry?

    Answer: Ventilate the space and verify benzene drops below 1 ppm, then re-test

    Benzene must be reduced below the OSHA PEL of 1 ppm through ventilation and confirmed by re-testing before entry is authorized.

  2. Which document provides the hierarchy of health hazard data sources a Marine Chemist should consult when evaluating an unknown shipboard cargo?

    Answer: The cargo's Safety Data Sheet (SDS) Section 2 and Section 11

    SDS Sections 2 (hazard identification) and 11 (toxicological information) are the primary sources for health hazard data on specific chemicals.

  3. During hot work in a tank that previously held crude oil, the atmosphere reads 0% LEL. A Marine Chemist must consider which additional hazard before issuing a Safe Work certificate?

    Answer: Residual liquid pooled under gratings that could vaporize when heated

    Residual liquid hydrocarbons trapped under gratings or in low spots can vaporize rapidly when hot work raises temperatures, creating an explosive atmosphere even when initial readings show 0% LEL.

  4. A cargo tank that carried methyl alcohol (methanol) shows 0 ppm on a combustible gas indicator (CGI) but the Marine Chemist still withholds the certificate. What is the most likely reason?

    Answer: Methanol is not detectable by most catalytic bead CGIs below its flash point

    Many catalytic bead combustible gas indicators are poorly sensitive to methanol; a zero reading may be a false negative, so a photoionization or colorimetric method should verify the atmosphere.

  5. The Threshold Limit Value-Short Term Exposure Limit (TLV-STEL) for hydrogen sulfide is 5 ppm. This means workers may be exposed to that concentration for a maximum of:

    Answer: 15 minutes, no more than 4 times per shift with 60-minute intervals between exposures

    ACGIH STELs permit exposure at the listed concentration for up to 15 minutes, repeated no more than four times per shift, with at least 60 minutes between each short-term exposure period.

  6. Which risk matrix element is used to calculate a risk priority number (RPN) in a chemical hazard assessment aboard a vessel?

    Answer: Severity × probability × detectability

    In FMEA-based risk matrices, the RPN is the product of severity, probability of occurrence, and detectability ratings.

  7. A Marine Chemist finds oxygen content at 19.2% in a cargo hold. Which statement best describes this condition?

    Answer: Entry is prohibited because oxygen-deficient atmospheres begin below 19.5%

    OSHA defines an oxygen-deficient atmosphere as less than 19.5% oxygen by volume, making the space an immediately dangerous-to-life environment requiring supplied-air or SCBA.