Tp-39 why should bilges be kept clean and free of oil drips?

Answer: to reduce the risk of pollution

A bilge is the lowest compartment on a ship or a boat below the waterline. Water from the rough seas, rain, leaks etc. collects in this area and is pumped out to prevent the bilge from becoming full. It also need to be cleaned and free of oil drips to reduce the risk of pollution. Bilge water commonly contain oil, fuel, and other contaminants like urine, detergents, solvents, thus even small amounts of such materials can cause problems when introduced into the marine environment. Some oil that spills into the water evaporates, but petroleum hydrocarbons can remain suspended, concentrate on the surface, or settle to the bottom of the water resulting to pollution.