Liability policies are triggered by insured events ‘occurring’ during the policy period. Difficulty in pinpointing the time of occurrence of latent diseases and gradual pollution has produced theories, not universally accepted, from the US: 1. Exposure theory. Injury is simultaneous with first exposure. All insurers on risk during the exposure period are liable on a time on risk basis; 2. Manifestation theory. Injury is deemed to occur when it is first diagnosed. Only the policy in force at time of discovery is liable – this theory is rarely applied. 3. Injury In Fact Theory. Policies are triggered only if in force when an actual injury occurs or progresses. No liability is triggered during dormant periods. 4. Triple Trigger Theory/Continuous Trigger Theory. Injury is deemed to occur at time of first exposure, during continuing exposure and at time of manifestation. Any policy in force at any stage will be liable. Issues also arise as to how limits of indemnity should be applied. See OCCURRENCE; STACKING OF LIMITS.

A US term describing the insurance of seagoing hulls, cargoes and liabilities. This distinguishes those insurances from inland marine and sometimes from inland waterway hull, cargo and liability insurances.
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Insurance coverage for vessels and property in ocean shipping. River marine is the term referring to coverage for inland shipments on water. Motor truck cargo refers to coverage for property transported over highways.