The U.S. Environmental Protection Agency (EPA) in April 2018 proposed relaxing standards related to how it assesses the effects of exposure to low levels of toxic chemicals on public health.

Now, correspondence obtained by the LA Times revealed just how deeply involved industry lobbyists and a controversial, industry-funded toxicologist were in drafting the federal agency's proposal to scrap its current, protective approach to regulating toxin exposure.

The proposed change came just two weeks after a top EPA official contacted toxicologist Ed Calabrese, whose claim that low doses of carcinogens and radiation are healthy stressors akin to physical exercise that activate the body's repair mechanisms has been panned by more mainstream researchers.

"I wanted to check to see if you might have some time in the next couple of days for a quick call to discuss a couple of items … " EPA deputy assistant administrator Clint Woods wrote to Calabrese.

The EPA's proposed regulation, signed by then-Administrator Scott Pruitt and published in the U.S. Government's Federal Register, copied Calabrese's recommendations to Woods almost verbatim.

Calabrese, who was also quoted in the EPA's press release for the proposal, celebrated the announcement in an email to former coal and tobacco lobbyist Steve Milloy, who served on President Donald Trump's EPA transition team.

"This is a major big time victory," Calabrese wrote. Milloy, who is also a Fox News commentator, replied that it was "YUGE."

The EPA's proposal is a departure from its long-time "linear no-threshold" approach to regulating the study of toxins: once a substance is found to be harmful at one level, the danger applies at all levels. In other words, there can be no safe level of radiation exposure.

Calabrese argues this approach is overly cautious and a financial detriment to industry. The new rule would require that regulators look at "various threshold models across the exposure range" for pollutants.

Low doses of otherwise toxic chemicals can be beneficial to human health in specific clinical situations, the LA Times noted, but experiments have produced mixed results and experts say it would be a risk to apply the findings to regulation for the general public.

"There is no way to control the dose a person gets from an industrial or agricultural chemical," David Jacobs, a professor of public health at the University of Minnesota, told the newspaper. "It's not being doled out in pills and monitored by a physician who can lower it if the patient isn't responding well."

The EPA has not announced a date for when it will make a decision on the rule proposal.

Health experts believe that if the EPA does adopt the rule, it could lead to wholesale changes to the agency's standards for regulating toxic waste, pesticides, and air and water quality.

"Industry has been pushing for this for a long time," George Washington University professor of environmental and occupational health David Michaels told the LA Times. "Not just the chemical industry, but the radiation and tobacco industries too."

Calabrese has long been connected to these industries and has received funding from tobacco firm R.J. Reynolds, Dow Chemical, Exxon Mobil and others, the LA Times reported.

Calabrese's role in the EPA's proposal illustrates how the Trump administration has pursued environmental policy recommendations from industry lobbyists based on research running counter to mainstream science.

According to the LA Times, Calabrese first emailed Milloy about whether it would be possible to get the EPA to abandon the linear no-threshold model in September 2017, not even nine months after Trump was sworn into office.