The Inspections and Compliance Directorate issued Marine Safety Alert 04-19, “Confined Spaces: Silent & Invisible Killers” to remind mariners that despite decades of work to improve confined space entry by maritime safety organizations, training institutions, and vessel owners/operators, the risks have not been eliminated. This is illustrated by a recent casualty where three persons were asphyxiated while working onboard a laid-up Mobile Offshore Drilling Unit (MODU).

https://mariners.coastguard.dodlive.mil/2019/04/17/4-17-2019-marine-safety-alert-confined-spaces-silent-invisible-killers/