Personnel from the Department of Interior's Bureau of Safety and Environmental Enforcement and the Coast Guard examined safety systems, the blowout preventer and other equipment on the Scarabeo 9 drilling unit off the coast of Trinidad and Tobago.
The inspection came at the invitation of Repsol, which plans to use the rig in Cuban waters later this year.
U.S. inspectors found the drilling unit was in compliance with international and U.S. standards for work in the offshore environment. They said, however, they hold no legal authority over operations in third-party economic zones, nor does their review constitute any sort of endorsement.
"The review is consistent with U.S. efforts to minimize the possibility of a major oil spill, which would hurt U.S. economic and environmental interests," the agencies said in a statement.
The U.S. Energy Information Administration estimates that, as of 2009, there are around 1 billion barrels of oil reserves in Cuba's economic zone. The country aims to cut the amount of oil it imports from Venezuela through development of offshore reserves.
A group of U.S. House of Representative lawmakers, all of Cuban descent, were critical of Repsol, saying its plans constitute work "with a state sponsor of terrorism."