The Investigations Department investigates reportable marine casualties under the authority of 46 USC 6301. The department determines the level of investigation by the regulations outlined in 46 CFR Part 4.

Activities Europe investigators conduct inquiries of violations of law or regulation, incompetency, or acts of misconduct or negligence by licensed or documented merchant mariners in Europe, Africa, and the Middle East.

 Investigators also audit the Marine Employer Chemical Testing Program to ensure compliance with 46 CFR Part 16.