WASHINGTON — Shortly before 10 p.m. on April 20, 2010, an explosion ripped through the Deepwater Horizon drilling rig in the Gulf of Mexico, unleashing the worst offshore oil spill in United States history and triggering what were supposed to be systemic changes to ensure such a disaster could never happen again.

Now, a decade later, all seven members of the bipartisan national commission set up to find the roots of the disaster and prevent a repeat said many of their recommendations were never taken seriously. As drilling moves farther offshore and deeper underwater, they said, another spill of equally disastrous proportions is possible.

All seven members, in fact, agreed that the United States was only marginally better prepared than it was the night eleven people died in the fiery blowout that released more than 3 million barrels of oil into the waters off the coast of Louisiana.

“No, I don’t think we’re prepared for another spill of that magnitude,” said William K. Reilly, the commission’s Republican co-chairman, who served as administrator of the Environmental Protection Agency under the first President George Bush.

That view is not shared by oil industry leaders or members of the Trump administration, who said government oversight and prevention technology had improved significantly over the past decade, making the likelihood of another major spill remote.

BP, which operated the Deepwater Horizon through a contractor, said the accident “forever changed” the company.

“In 2010, we promised to help the Gulf of Mexico recover, become a safer, better company, and report on our progress,” the company said in a statement. “The lessons we’ve learned and the changes we’ve made — from tougher standards to better oversight — are at the core of becoming a safer company.”

But in lengthy interviews this month, every member of the bipartisan panel, the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, accused the Trump administration of putting American waters, coastlines and wildlife in harm’s way by weakening safety and environmental regulations while pushing to expand oil drilling in nearly all American waters.