President Donald Trump’s administration announced Friday that the Environmental Protection Agency is relaxing Obama-era rules preventing coal-fired power plants from releasing mercury and other dangerous pollutants into the air.

The proposed change ― which EPA acting administrator Andrew Wheeler signed on Thursday and will be up for 60 days of public comment before a final ruling goes into effect ― does not outright repeal the 2011 mercury limit regulation but paves the way for doing so by stating the program’s effectiveness should be judged only by “the benefits that can be directly translated into dollars and cents,” as The New York Times put it.

Mercury exposure is linked to developmental disorders, respiratory illnesses and cancer. The new rule would not factor in the harder-to-quantify benefits linked to preventing those health consequences, such as protecting fetuses whose intelligence could be affected in the long term by the amount of mercury their mothers ingested when they were pregnant with them.

“The administrator has concluded that the identification of these benefits is not sufficient, in light of the gross imbalance of monetized costs,” the EPA announcement read, bucking the Obama administration’s conclusion that the mercury rule should be evaluated on factors beyond monetary costs.

If the change is finalized, the mercury rule could be opened up to clearer legal challenges in court, and other clean air regulations may also be put at risk.

The change would also be a financial windfall for the coal industry. The mercury rule costs the coal industry $9.6 billion a year ― making it one of the most expensive regulations ever issued by the EPA.

But the proposal reverses a decades-old finding ― reaffirmed twice by the EPA ― that the agency was within its legal grounds to control emissions of power-plant mercury and other dangerous pollutants linked to respiratory illnesses, neurological damage and cancer.

“What has changed now is the administration’s attitude towards public health, and towards the coal industry” Ann Weeks, legal director of the nonpartisan Clean Air Task Force, said in a statement. “EPA proposes to disregard many of the important public benefits that result from controlling all the toxic air emissions from this industry.”

In 2011, the EPA’s own analysis determined that the rule would prevent up to 11,000 premature deaths, 130,000 asthma attacks and 5,700 hospital visits every year, and save taxpayers $90 billion in health care costs annually.

“Children are especially vulnerable to environmental changes as they are smaller in size, breathe faster than adults, and experience rapid and critical periods of growth and development,” Colleen Kraft, president of the American Academy of Pediatrics, said in a statement. “We urge the EPA to maintain these critical standards, and call on Congress to protect the MATS rule so that all children, regardless of their ZIP code, can breathe clean air.”

This story has been updated with comment from Ann Weeks and Colleen Kraft.