Reports of an underwater UXO clearance technology claiming to be harmless to the marine environment is challenged in an IMCSE Technical Publication. The published pressure measurements, indicating that there had been at least partial detonations, were reported to have presented a risk of harm to wildlife (Harbour Porpoise within approximately 4km) despite the results not having breached the operator’s licence thresholds. The latest data from trials conducted by the national Physical Laboratories and Loughborough University might offer guidance for more stringent but achievable thresholds for future work. The Technical Paper is available in the Members section, nonmembers with a bona fide interest in the subject may request a copy by applying to editor@imcse.org