This document provides guidance on taking and handling samples that are collected as part of an investigation into the likely source of a crude oil or petroleum product spill into a marine or aquatic environment. Guidance is given on taking samples from both the spill and its potential source.If samples are to be used in connection with legal proceedings, this document should be read in conjunction with any documents issued by the regulatory authorities in the country and location where the spill has occurred.Taking samples may involve hazardous materials, operations and equipment. This document is not intended to address all the safety and health aspects a