The U.S. Interior Department issued a safety alert on Feb. 2, warning offshore oil and gas drillers about a "recurring problem of connector and bolt failures" in equipment including blowout preventers.

The Bureau of Safety and Environmental Enforcement (BSEE), a unit of the department, said it was aware of the problem, which affected components used in risers and underwater blowout preventers used in offshore drilling.

"These failures are of great concern to BSEE due to their frequency and the potential for a catastrophic event," the agency said. In 2012, failures led to a global recall of bolts and a temporary stop to drilling activities, BSEE said.

BSEE recommended that drilling operators work with the original equipment manufacturers to verify all components satisfy the metallurgical properties specified by the makers and to follow installation and maintenance procedures.