CMC Hazardous Materials Management & Containment 2

Question 1

Under NFPA 306, what oxygen concentration range is considered 'safe' for normal entry into a marine vessel space?

Accepted Answer

19.5%–22.0%

Answer

NFPA 306 defines a safe oxygen atmosphere as 19.5% to 22.0% by volume for normal entry.

Question 2

Which document must a Certified Marine Chemist issue before hot work is permitted in or near a confined space on a vessel?

Accepted Answer

Certificate of Fitness

Answer

A Marine Chemist Certificate of Fitness (or Safe-for-Hot-Work certificate) is required before hot work begins on or near vessel spaces.

Question 3

A cargo tank that previously held benzene is classified as 'Not Safe for Workers' primarily because benzene's IDLH is:

Accepted Answer

50 ppm

Answer

NIOSH sets benzene's IDLH at 500 ppm, but OSHA's permissible exposure limit (1 ppm) and carcinogenicity mean even low concentrations preclude worker safety.

Question 4

When a hazardous material spill occurs in a vessel's bilge, the FIRST action under MARPOL Annex I is to:

Accepted Answer

Transfer the mixture to a slop tank and prevent overboard discharge

Answer

MARPOL Annex I requires preventing unauthorized overboard discharge; spilled oily mixtures must be contained and transferred to a slop tank pending proper disposal.

Question 5

The Lower Explosive Limit (LEL) of a flammable vapor represents the concentration at which:

Accepted Answer

The air-vapor mixture is too lean to ignite

Answer

The LEL is the minimum concentration of flammable vapor in air below which ignition cannot propagate because the mixture is too lean.

(CMC) Certified Marine Chemist Practice Test

(CMC) Certified Marine Chemist Practice Test

CMC Hazardous Materials Management & Containment 2