Washington DC - Former heads of the Environmental Protection Agency (EPA) have warned that President Donald Trump's rollbacks of key regulations could cause "severe harms" and even put lives at risk.

Three former heads of the EPA joined forces on Friday to sound the alarm against massive deregulations planned under the agency's new administrator Lee Zeldin.

Last week, Zeldin revealed a massive string of rollbacks at the EPA, including the decision to repeal the 2009 Endangerment Finding, which established that greenhouse gases can cause harm to human health.

Gina McCarthy, who served as EPA administrator between 2013 and 2017 under President Barack Obama, called Wednesday "the most disastrous day in EPA history," The Guardian reported, as Zeldin rolled back 31 environment rules, including regulations on clean air and water.

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"This EPA administrator now seems to be doing the bidding of the fossil fuel industry more than complying with the mission of the EPA," said McCarthy.

William K. Reilly, who led the agency under President George HW Bush called Zeldin's moves a "catastrophe" for the US and said the new trajectory "represents the abandonment of a long history."

"What this administration is doing is endangering all of our lives – ours, our children, our grandchildren," said Christine Todd Whitman, who held the position during the George Bush administration in the 2000s.

Whitman was referencing the repeal of the 2009 Endangerment Finding, a bedrock of US law on which many environmental regulations are based.

"We all deserve to have clean air to breathe and clean water to drink," Whitman continued. "If there’s an endangerment finding to be found anywhere, it should be found on this administration because what they’re doing is so contrary to what the Environmental Protection Agency is about."