Exactly five years since the BP oil spill began in the Gulf of Mexico, an expert has warned the industry is "setting the stage" for an even worse explosion.

A blast on the Deepwater Horizon drilling rig in April 2010 killed 11 men and left hundreds more injured. It was the worst offshore spill in US history, lasting for nearly three months.

According to new research, drillers in the region are now exploring reserves of oil and natural gas at depths of 20,000 feet (6,095m) underneath the seabed – far beyond where the BP rig was operating when it suffered a blowout.

At the time, Deepwater Horizon was seen as such a difficult site that one worker, who died in the explosion, described it as the "well from hell" – and temperatures and pressures will be far more intense in these new, ultra-deep sites.

But despite the elevated risks of drilling at such unprecedented depths, energy companies have been accused of failing to develop stringent safety measures which would prevent another environmental disaster – or, at least, contain it.

Matthew Franchek, from the University of Houston, said: "It's not rocket science. Oh, no, it's much, much more complicated."

The area now being explored has been described as a "golden zone" with the potential to yield 300,000 barrels of oil every day – and as such rigs would contain larger amounts of oil than the BP well did, there are concerns that any future spillage could be even more devastating to local communities.

Richard Charter, a senior fellow with the Ocean Foundation, said: "We're setting the stage for the next Macondo blowout, and even worse."

Although the companies at the forefront of ultra-deep exploration, including BP, Shell, Chevron and Conoco-Phillips, acknowledge the challenges of plundering these new depths, they insist safety is now a number one priority.

More inspectors have been hired, and cash has been invested in inventing sophisticated equipment should a clean-up be necessary.

Geoff Morrell, a spokesman for BP, said the safety culture within the company has vastly improved since 2010.

However, the US Chemical Safety Board has recently discovered "serious" and "fatal" design flaws with the large valves used to prevent a blowout across the Gulf.

"We have this desperate need for energy, and we have to go after it wherever it is," said Stephen Colville, president of the International Association of Drilling Contractors.

Please leave comments and feedback below