A push by Donald Trump’s administration to repeal a barrage of clean air and water regulations may deal a severe blow to US public health, with a Guardian analysis finding that the targeted rules were set to save the lives of nearly 200,000 people in the years ahead.

Last week, Trump’s Environmental Protection Agency (EPA) provoked uproar by unveiling a list of 31 regulations it will scale back or eliminate, including rules limiting harmful air pollution from cars and power plants; restrictions on the emission of mercury, a neurotoxin; and clean water protections for rivers and streams.

Lee Zeldin, the EPA’s administrator, called the extraordinary series of rollbacks the “greatest day of deregulation our nation has seen” and declared it a “dagger straight into the heart of the climate change religion”. One of the most consequential actions will see the EPA reconsider a landmark 2009 finding that greenhouse gases harm human health, which has been used to underpin laws aimed at addressing the climate crisis.

But the rules targeted by Zeldin have immediate, measurable benefits to Americans’ health even without considering the longer-term impacts of the climate crisis. In total, the regulations on the hit list will prevent nearly 200,000 deaths over the next 25 years, by helping avoid an array of heart, respiratory and other health problems worsened by air and water pollution, according to assessments conducted by the EPA itself.

Trump’s EPA has said its immolation of environmental protections will “roll back trillions in regulatory costs and hidden ‘taxes’ on US families”. However, the agency’s own analyses shows that the regulations save the US economy far more money than it costs businesses to implement new pollution controls, by a factor of around six to one.

The regulations slated for repeal, affecting coal plants, cars, trucks and other sources of pollution, had been set to deliver at least $254bn in economic benefits annually via lowered healthcare costs and fewer sick days, among other improvements. By contrast, the cost of complying with the regulations is around $40bn a year.

“The costs of these regulations are a fraction of their benefits,” said Jeremy Symons, a former EPA staffer, now senior adviser to the Environmental Protection Network (EPN), a group made up of former EPA employees.

“For every million dollars of favors that Trump’s EPA is handing out to corporate polluters, the public suffers $6m in public health costs through asthma attacks, cancers and heart and lung disease. That’s a great deal for the wealthy corporate polluters who backed Trump but it’s a bad deal for anyone else who breathes.”

The Guardian’s analysis is drawn from the findings of an EPN report published last year that broke down the costs and benefits of EPA rules. The study looked at evidence gathered by the EPA when formulating each new rule, factored in inflation and verified with the agency a uniform extrapolation of these figures to 2050.

Of the 31 rollbacks announced by Zeldin, 11 can be analyzed in this way as they include assessments of health and economic impacts. The estimates used by the EPA are almost certainly undercounts as they often do not factor some health conditions, such as cancer, nor do they account for damages from wildfires, floods, storms and other disasters that are being worsened by a climate crisis that is being driven by fossil fuel pollution.

As well as scores of deaths, a wave of other harms would likely be unleashed if the targeted regulations were removed. More than 20,000 emergency room visits for cardiovascular problems would occur by 2050 if not for the rules, the analysis finds, while children would have to restrict their activities for a collective 89m days due to excess pollution.

About one in 12 Americans, meanwhile, have asthma and are particularly vulnerable to air pollution. The current limits upon emissions from coal-fired power plants, cars, trucks and other sources are on track to avoid 100m symptomatic asthma incidents across the US by 2050. “If you carry around an inhaler, these rollbacks are a nightmare,” said Symons.

“The rollback of these critical public health interventions will increase heart attacks, hospitalizations, cognitive impairment, respiratory disease, and healthcare costs,” said Gaurab Basu, an assistant professor of medicine climate expert at Harvard University. “It will leave our children facing an increasingly unstable planet Earth.”

The Trump administration is attempting to severely shrink the EPA, firing hundreds of employees and drawing up plans to remove as many as 1,155 scientists while dissolving the agency’s office of research and development. But it cannot simply sweep aside EPA regulations, which require several years of grueling agency work and public comment to replace.

John Walke, a director at the green non-profit Natural Resources Defense Council, said it will be difficult for officials to justify the changes. One now-slashed Biden-era rule limiting power plants’ emissions of mercury and other hazardous air pollutants, for instance, simply saw regulators codify pollution standards that most power providers had been meeting for years.

“If this administration tries to go in to change that, they’re going to have to show that somehow is impossible for those facilities to meet standards they were already meeting,” he said. “They’re just not going to be able to make that showing.”

Environmental groups have vowed lawsuits to fight the rollbacks, meaning that a diminished EPA is faced with a mountain of legal and administrative paperwork just as Zeldin has promised to cut the agency’s spending by 65% this year.

“A rule is based on science and study, you have to come up with alternative science that makes sense,” said Christine Todd Whitman, who was the EPA administrator under George W Bush, about rule re-writes. But Whitman said that recent mass firings of EPA staff and a drop-off in enforcement activity will in practice make it difficult to uphold existing anti-pollution laws.

“The message to businesses is ‘we won’t enforce what we are already doing,’” she said. “Real people will be hurt, especially children. We need to all be concerned about this. What this administration is doing is endangering our lives – ours, our children’s, our grandchildren’s.”

A deeper fear expressed by former EPA administrators last week, from prior Democratic and Republican presidencies, is that the agency won’t bother to even craft weaker regulations to replace the existing rules. The goal may be “not to reconsider the rules but to bury them”, said Gina McCarthy, the EPA chief under Barack Obama. “If that’s the case that’s now being thrust upon us then shame on the EPA’s leadership.”

McCarthy said the announcement of the mass rollbacks was the “most disastrous day in EPA history” and signaled a stark break from its historic mission. The agency was founded in 1970 under Republican president Richard Nixon with a task of protecting the environment and public health. Under Trump, however, the EPA has installed industry lobbyists in key positions and its stated priorities now include boosting the US car industry and aiding the advance of artificial intelligence.

“Alongside President Trump, we are living up to our promises to unleash American energy, lower costs for Americans, revitalize the American auto industry,” Zeldin said last week.

William Reilly, who was EPA administrator under George HW Bush, said that such a vision is a “catastrophe” and threatens to plunge the US back into a pre-1970s era when cities were routinely shrouded by dangerous smog and rivers were so polluted by chemicals and waste that in some cases they caught fire.

“We are almost going to an honors system where we are going to trust corporations behave as if there are laws, when there are no laws,” Reilly said. “I honestly wonder if the malefactors are going to give us more burning rivers.”

An EPA spokesperson said: “No longer will the EPA view the goals of protecting our environment and growing our economy as binary choices. We will and we must choose both.

“Under President Trump, EPA is fully committed to fulfilling all of our statutory obligations under the many bipartisan landmark laws that help ensure clean air, land, and water.”