Vessel-Specific Hazards 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 Vessel-Specific Hazards flashcards as text
Under NFPA 306, which authority has the power to revoke a marine chemist's certificate once it has been issued?
Answer: The marine chemist who issued it, or another qualified marine chemist
A certificate issued by a marine chemist can only be revoked by a qualified marine chemist; however, responsible parties must stop work if conditions change materially from those at certification.
A vessel's cargo pump room contains a fixed gas detection system showing safe readings. A marine chemist prepares to enter. What additional step is required under safe entry protocols?
Answer: Independent portable instrument testing at the entry point and throughout the space before entry
Fixed gas detection systems provide monitoring at fixed points only; independent portable instrument testing is required to verify the atmosphere at the specific point of entry and to detect hazards in areas not covered by fixed sensors.
What vessel-specific condition requires a marine chemist to test for carbon dioxide (CO2) as a primary asphyxiation hazard rather than just oxygen deficiency?
Answer: Both B and C are correct
Both fixed CO2 suppression system-protected spaces and cold storage areas using dry ice can contain elevated CO2 concentrations that displace oxygen and are directly toxic, requiring specific CO2 measurement beyond simple O2 monitoring.
On a vessel loaded with ammonium nitrate fertilizer, a marine chemist detects temperature elevation in the cargo hold. Beyond explosion risk, what toxic decomposition product is the immediate concern?
Answer: Nitrogen oxides (NOx) and ammonia from thermal decomposition
Thermal decomposition of ammonium nitrate produces toxic nitrogen oxides and ammonia gas, which are acutely toxic and can affect personnel before explosive decomposition occurs.
Which scenario on a tank vessel requires the marine chemist to verify the vessel's intrinsic safety rating of electrical equipment before issuing any certificate?
Answer: Certifying spaces on vessels carrying cargoes with flash points below 60°C (140°F)
When certifying spaces where flammable vapors may be present (flash point below 60°C cargoes), electrical equipment used in or near those spaces must be intrinsically safe or explosion-proof to eliminate ignition sources.
A marine chemist issues a 'Safe for Hot Work' certificate at 0800 hours. At 1400 hours, what is the maximum duration the certificate remains valid without re-inspection under standard NFPA 306 practice?
Answer: Certificates are typically valid for one work shift or until conditions change, requiring re-inspection before next shift
Under NFPA 306, hot work certificates are typically valid for one work shift, and a new inspection must be conducted before work resumes on the next shift or if conditions change materially.
What specific hazard does a 'slop tank' on a crude tanker present that other cargo tanks on the same vessel may not?
Answer: Combined hazards of flammable hydrocarbon vapors, toxic H2S, and potentially oxygen-deficient atmosphere simultaneously due to mixed residue accumulation
Slop tanks accumulate mixed residues from tank washing—oil, water, sludge, and sulfur compounds—creating the simultaneous hazards of flammability, H2S toxicity, and oxygen deficiency from decomposition, making them among the most dangerous spaces on a tanker.