(Reuters) - The Trump administration on Tuesday said it rejected a recommendation from staff scientists at the Environmental Protection Agency to tighten air quality regulations governing soot pollution, arguing the current standards are adequate to protect human health.

FILE PHOTO: Steam rises from a boiler stack at the Sugar Cane Growers cooperative in Belle Glade, Florida January 6, 2010. REUTERS/Carlos Barria

The decision marks a win for industries that had lobbied against a tightening of the standards, but triggered a backlash among activists and lawmakers who said soot remains a public health hazard and pointed to research showing it has also elevated death rates during the coronavirus outbreak.

“We believe that the current standard is protective of public health ... and does not need to be changed,” EPA Administrator Andrew Wheeler said in a conference call with reporters announcing the decision.

He said it followed a review of scientific research and consultations with the EPA’s independent science advisers, but acknowledged there are “still a lot of uncertainties” around fine particulate matter.

At issue is the National Ambient Air Quality Standards regulation, which sets limits on the concentrations of different pollutants in the air - including soot from coal- and gas-fired power plants and vehicle tailpipes.

The EPA is required to review the standards every five years, and has tended to tighten them regularly.

The current standard set in 2012 allows for 12 millionths of a gram of fine particles per cubic meter of air. Parts of the country that exceed that standard are declared out of compliance, which sets in motion limits on new industrial development until air quality improves.

EPA staff had recommended that the standard drop to 8 millionths of a gram per cubic meter, after research showed respiratory damage could occur at current standards.

Harvard University this month also published research showing that the coronavirus causes a higher death toll among patients in parts of the country with increased levels of fine particulate pollution.

In a letter to Wheeler on Tuesday, a group of 18 Democratic and independent senators led by Maggie Hassan of New Hampshire blasted the EPA’s decision. “The Environmental Protection Agency should be taking actions that will further protect health during this crisis, not put more Americans at risk,” they wrote.

Environmental advocates also criticized the move.

“It’s especially egregious that EPA is making this announcement in the thick of the COVID-19 pandemic - a public health crisis that evidence increasingly suggests is dangerous to people living in areas with higher air pollution levels,” said Gretchen Goldman, research director at the Union of Concerned Scientists advocacy group.

“This administration is passing up an opportunity to make the air cleaner for millions of Americans - choosing instead to do nothing. That’s indefensible,” said former EPA Administrator Gina McCarthy, who is now head of the Natural Resources Defense Council.

Wheeler noted that the Harvard study had not been peer reviewed.

The American Petroleum Institute, which represents U.S. oil and gas companies, praised the move and pointed out that particulate pollution had dropped in recent years.

“Many industry groups across America – including ours – agree that EPA’s proposed rule is a smart balance that will further reduce emissions and help protect public health while meeting America’s energy needs,” said API Senior Vice President of Policy, Economics and Regulatory Affairs Frank Macchiarola.

The EPA has made a number of other controversial moves in recent weeks, including finalizing a rollback of Obama-era vehicle fuel efficiency standards and announcing an easing of regulatory enforcement on companies affected by the coronavirus.

Trump has made it a priority since taking office to roll back environmental regulations he believes are an obstacle to economic development.