Bureau of Safety and Environmental Enforcement Director Jim Watson launched an unannounced drill in the Gulf of Mexico to test equipment meant to respond to an incident like the 2010 Gulf of Mexico oil spill.
"We fully expect operators to have the plans, equipment and capabilities in place to respond to a subsea blowout in deep water at a moment's notice," Watson said in a statement.
The deep-water Macondo oil well failed in 2010 and sparked an explosion on the Deepwater Horizon oil rig, killing 11 workers and leading to one of the worst oil spills in industry history.
Helix Well Containment Group used a so-called capping stack system that would stop the flow of oil and gas underwater in the event of a disaster like Macondo's. Noble Energy served as the designated operator.
Another consortium, the Marine Well Containment Co., conducted a similar drill in July.
Reforms enacted after the 2010 spill require well operators to show there are adequate response mechanisms in place should a well failure occur in deep water.