Commercial divers working offshore are sometimes required to dive in situations where there may be contamination in the water or on the seabed. This contamination can be due to the presence of drill mud and cuttings or can be due to the work the diver is required to carry out, such as recovering drums of chemicals, breaking of flanges, working on pipelines etc. It may also be due to general contamination by heavy metals, chemicals, radioactivity, biological material or similar in the area that the work has to be carried out.

One of the problems faced by diving contractors is that the operator, owner of the area or client may not be able to provide any detailed information to the diving contractor about the exact composition of the suspected contaminants.

An IMCA workgroup assembled in 2004 reviewed, expanded and updated previous guidance to produce this document which considers all of the available evidence and addresses issues such as decontamination procedures which need to be addressed when diving in potentially contaminated waters.

The basic and obvious advice from which the recommendations in the document flow is as follows:

• an adequate safety management system
• hazard identification and a detailed risk assessment. This assessment should result in the selection of suitable protective equipment and procedures in order to carry the operation out safely
• adequate briefings of all involved personnel
• consideration of all reasonably foreseeable emergencies.