Oil mist

It sinks easily, reducing fire hazard.

Oil mist inside the crankcase can cause a bigger problem.

When the concentration of oil mist increases and reaches the lower explosion limit (LEL; 50 mg/ℓ, as defined by the IACS), explosion may occur when the mist contacts surfaces of over 200 °C (392 °F) or a spark.

The International Association of Classification Societies (IACS) mandates that all ships with a cylinder diameter greater than 300mm or engine power over 2,250 kW must be equipped with either bearing temperature detectors or oil mist detectors.

[3] 1 International Maritime Organization (IMO) 2 International Association of Classification Societies Ltd unified requirements concerning MACHINERY INSTALLATIONS 3 Oil Companies International Marine Forum Ship Inspection Report (SIRE) Programme/ Vessel Inspection Questionnaires for Oil Tankers, Combination Carriers, Shuttle Tankers, Chemical Tankers and Gas Carriers