The Trump Administration's proposed slashing of the Environmental Protection Agency's budget threatens to reduce the agency's resources to levels not seen since its formative days, long before demands from Congress and the public expanded the scope of the agency's missions.

Spending reductions of nearly 25 percent and layoffs of thousands of employees have been floated. Climate change-related programs have been targeted for outright elimination. But that's also enough to cripple some of the agency's core activities, according to experienced agency veterans and outside experts.

Already, the EPA's budget has been cut 7 percent and the agency has lost about 2,000 full-time employees in about five years. The White House budget plan would slash the agency to 12,000 people—setting the agency back to staffing levels of the late Reagan administration. EPA's funding would fall $2 billion to $6.1 billion. When inflation is taken into account, that would be its lowest point since the Ford administration.

With cuts on that scale, EPA would have to function with resources comparable to its earliest years, shortly after its founding under Richard Nixon.

That was before the rise of the Superfund toxic dump cleanup program in 1980, the revisions to the Clean Air Act that in 1990 created economy-wide pollution permitting, the changes to the Safe Drinking Water Act that passed Congress overwhelmingly in 1986, and the growing complexity of dealing with pollution from pesticides, dioxins and other chemicals.

"I believe EPA has been run on a shoestring for a long time," said Bruce Buckheit, a former EPA lawyer who worked on pollution enforcement, a central task for the agency. "You're past the point where you have fat to cut."

'Everything We Do Is Related to Climate Change'

Trump's proposed cuts to the EPA, floated in leaked internal memos and vague announcements, appear to single out climate change programs for cancellation, making good on his campaign promise to "unleash" fossil fuel production. And because so many types of pollution are created by producing and burning fossil fuels, the assault on climate protections could also affect EPA actions that don't address climate change directly—including those that deal with pollutants like smog, soot, acid rain and mercury, or with cleanup operations, or sewage.

The climate cuts would also hit agency research studying ways global warming is affecting EPA's mission to protect the public against day-to-day pollution.

"You can't separate urban air quality and ozone levels from the impacts of weather," said Thomas Burke, an associate dean at the Johns Hopkins Bloomberg School of Public Health. "You can't build a sustainable community anymore without thinking about controlling for very extreme climate events."

He cited the case of Toledo, Ohio's drinking water crisis in 2014, when the water supply was shut down because of a toxic algae bloom in Lake Erie—an acute symptom of a chronic climate disease.

"When you examine why that algal bloom is there," he said, "you have to look at things like water temperatures are different, and storm events that are different."

Burke, who led scientific research at EPA in the final years of the Obama administration, was one of three bipartisan agency veterans to plead last week in the New England Journal of Medicine against cuts in environmental protection, including climate action.

One career EPA official who is knowledgeable about the agency's climate programs but asked not to be named, lamented how little is known about the agency's climate work and its connection to clean air and water. "A lot of people look at EPA and they think we do these big global climate models. That's not what we do," the official said. "We focus on how we at EPA are going to be able to meet our requirements for clean air and clean water—what's in the law for us to do—as the climate changes."

The 30 agency scientists who focus on climate, for instance, recently tackled issues such as how worsening wildfires affect air quality; how drinking water treatment is affected by extreme weather; and how to stop the release of toxic contaminants from waste sites during flooding.

"Everything we do [at EPA] is related to climate change, and climate change is related to everything we do," the official said. "It's another stressor, another component of risk we have to account for."

Because it's unlikely other government agencies will take up that effort, and the private sector has no incentive to do it, "that's why we're involved," the official said. "The states turn to us."

The Trump team is working from a blueprint budget developed by the Heritage Foundation, a conservative think tank that rejects the prevailing scientific consensus on climate change and the need to urgently address it, including at the EPA.

Its blueprint would end the effort to regulate greenhouse gases in vehicles, power plants or other man-made sources. It would eliminate the Greenhouse Gas Reporting Program, under which industrial facilities have been reporting their carbon emissions since 2010. It would stop "climate resilience" funding, like the grants to help coastal communities protect and enhance wetlands to protect against sea level rise and storm surge.

How deeply the White House and Congressional leaders end up cutting remains anyone's guess.

Last week EPA staff received a memo from acting administrator Donna Vizian. "We are in the first part of a long engagement between the executive and congressional branches of the federal government to establish our appropriation level for FY 2018," which begins on October 1, she said.

What will happen when funding this year under a temporary stopgap spending bill runs out at the end of April? She said she was in the dark. "The Congressional appropriations staffs are working on this, but we have not seen any recent numbers from their process," she wrote.