A group of US experts led by a former top environment official has visited Cuba to gather information on the communist country's Gulf of Mexico oil exploration plans, according to state media.

William Reilly, who led the US Environmental Protection Agency (EPA) under former president George H.W. Bush and led a commission on the BP oil spill disaster in the Gulf until January, was reportedly leading the US delegation.

US media reported that Reilly was traveling to Cuba Monday with other experts. "The team is not traveling to Cuba in any official capacity," a State Department official said privately.

Cuba, the Americas' only one-party communist regime, and the United States do not have full diplomatic relations. Under an economic embargo, US oil companies are shut out of potential earnings from Cuba's prospecting.

And US lawmakers -- especially from US states on the Gulf of Mexico that took a massive economic and environmental hit from the 2010 Deepwater Horizon disaster and spill -- are concerned Cuba might be unprepared or unable to take proper environmental precautions to prevent another.

A presidential commission concluded last October that a faulty cement mix in the lining of the well contributed to the BP disaster, which killed 11 workers.

Some 4.9 million barrels of oil had gushed out of the runaway underwater well -- causing severe environmental damage in the Gulf of Mexico -- before the leak was capped about three months later.

"We expect any company operating in Cuba?s oil and gas sector to adhere to industry environmental, health, and safety standards, and to have adequate prevention, mitigation, and remediation systems in place in the event of an incident," the statement from the US State Department spokesman said.

Among the recommendations to the White House of the commission Reilly led were to iron out joint exploration and safety standards among Cuba, Mexico and the United States.

Reilly has convinced Mexican authorities to sign on but his earlier efforts to visit Cuba hit some State Department resistance, The New York Times reported in May.

Cuba in April announced plans to drill five deep water oil wells in the Gulf of Mexico beginning this summer, expressing confidence that its efforts will be rewarded with major new energy finds.

Manuel Marrero, an official with the government authority tasked with overseeing Cuba's oil sector, said at the time the ventures would be undertaken with the help of unspecified foreign companies.

He said the deep water wells were to be drilled between 2011 and 2013, and would be in waters ranging in depth between 400 meters (a quarter mile) and 1,500 meters (1.6 miles).

He did not specify which countries would be among the foreign partners working with Havana on the project.

Some studies estimate Cuba has probable reserves of between five and nine billion barrels of oil in its economic zone in the Gulf of Mexico. Cuban authorities have said their crude reserves are as high as 20 billion barrels.

In 2010, Cuba produced 21 million barrels of oil, about the same as it had extracted the previous year, representing a little less than half of its annual energy needs.

Cuba has long been plagued by energy dependence, its economic Achilles' heel. Havana used to depend on the eastern bloc for cut-rate oil and plunged into economic chaos and blackouts when it was cut off after 1989.

Now Cuba depends on Venezuela -- its vital economic and political ally -- for the rest of its oil imports of about 100,000 barrels per day. Any cut to Venezuelan supplies could spell political and economic disaster for Havana.

But if Cuba locks in its energy independence, it could lurch from a cash-strapped developing nation into a flush oil exporter, and potentially project its current regime years into the future.

Cuba's economic zone in the Gulf is divided into 59 blocs. They include ventures with Repsol (Spain), Hydro (Norway), OVL (India), PDVSA (Venezuela), Petrovietnam, Petronas (Malaysia) and Sonangol (Angola). China and Venezuela have said they intend to help Cuba triple its refining capacity by 2017.