Before welding can be done in a tank that has carried petroleum products，a certificate must be obtained from（）.

单项选择题（）is not a process of weathering of the oil spilled in the sea water.

A.Biodegradation
B.Dissolution
C.Cleaning up by crew with skimmers
D.Oxidation including photooxidation

单项选择题A petroleum liquid has a flash point of 135°Fahrenheit. This liquid is classed as a grade （）.

A.B flammable liquid
B.C flammable liquid
C.D combustible liquid
D.E combustible liquid

单项选择题A 30，000 DWT tanker is required to have an IOPP certificate when（）

A.engaged in the coastwise trade
B.going foreign
C.calling at ports in another country signatory to MARPOL 73/78
D.carrying cargoes listed in the MARPOL regulations

单项选择题Regulations require that cargo pumprooms on tank barges (constructed in 1965) carrying grades B or C liquid cargoes have power ventilation systems which can completely change the air in （）.

A.1 minute
B.3 minutes
C.5 minutes
D.10 minutes

单项选择题Regulations require that cargo tanks carrying grades D or E liquids on tank barges be vented with（）.

A.gooseneck vents and flame screens
B.pressure-vacuum relief valves
C.branch vent lines and a vent header
D.forced draft blowers