Nearly 600 former Environmental Protection Agency (EPA) officials are asking House leadership to investigate the agency for appearing to place undue focus on California’s pollution enforcement, an act they argue is politicized.

In a Thursday letter sent to both the House Oversight and Reform Committee and the Energy and Commerce Committee, the former EPA employees ask Democratic leadership to investigate whether warnings issued by Administrator Andrew Wheeler Andrew WheelerOvernight Energy: Trump officials finalize plan to open up protected areas of Tongass to logging | Feds say offshore testing for oil can proceed despite drilling moratorium | Dems question EPA's postponement of inequality training Democrats question EPA postponement of environmental inequality training OVERNIGHT ENERGY: California seeks to sell only electric cars by 2035 | EPA threatens to close New York City office after Trump threats to 'anarchist' cities | House energy package sparks criticism from left and right MORE to California in September, regarding the state’s homeless population and pollution concerns, were done as retaliation for ongoing pushback to President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE’s air enforcement agenda.

“EPA’s credibility depends on its commitment to use its authority to protect public health and our environment in an objective, even-handed manner, rather than as a blunt instrument of political power. While that principle has served the public well under both Republican and Democratic Presidents, it is in serious trouble today,” read the letter, signed by former Obama EPA Administrator Gina McCarthy Regina (Gina) McCarthyFormer EPA chiefs endorse Biden, criticize agency direction under Trump OVERNIGHT ENERGY: Energy Department proposes showerhead standards rollback after Trump complaints | Interior memo scaling back bird protections is 'contrary to law,' court rules | Former EPA chiefs call for agency 'reset' Former EPA chiefs call for agency 'reset' MORE and others.

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In late September.

Wheeler sent a letter to California Gov.

(D) criticizing the state for "failing to meet its obligations" on sewage and water pollution, blaming homelessness for the contamination. The letter specifically knocked San Francisco. It was the latest move in the political battle between Trump and the nation’s largest state, and one experts have said carries

.

The EPA pushed back in a statement, saying California’s failures on air and water create “pubic health risks” for its population.

"Highlighting that California has the worst air quality in the nation along with other serious environmental problems is not a political issue. The Trump Administration, unlike the previous administration, will act to protect public health and the environment for all Americans," EPA spokesman Michael Abboud said.

The letter from the former employees comes as the Environmental Integrity Project unveiled an investigatory deep dive that found via the EPA’s enforcement database that many states, not just California, were out of compliance with EPA regulations when it comes to wastewater discharge violations.

According to the internal EPA data, Ohio, New York and Iowa were the biggest offenders.

The group found 429 major sources across the country are in “significant noncompliance” for either discharging more pollution than allowed under their permits or for not meeting deadlines for compliance. All of the information they highlighted is found publicly on EPA’s website.

“On September 26, you wrote to the Governor of California to express concern about, 'numerous exceedances' of Clean Water Act discharge limits for major sources and noted that the violations were serious enough to, 'suggest the need for more formal and in-depth EPA oversight.' We ask that you give equally close scrutiny to Clean Water Act violations at large municipal or industrial wastewater treatment plants in other states,” the group wrote in a separate letter to Wheeler on Thursday.

While Wheeler, who is from Ohio, said the EPA keeps an eye on all states that fall behind their pollution enforcement obligations, he said in September that California was the only state to receive such a warning.

“Andrew Wheeler should look at his own backyard, if he wants to pick on a state,” said Tom Pelton, EIP director of communications.

He said the argument that the EPA worried about enforcement was disingenuous.

“If they are going to be interested in enforcement, that would be a first for them because they've seen a significant decline in enforcement under the Trump administration.”

He said the numbers showed the EPA’s sharp focus on California was unwarranted.

“It appears to be an improper political weaponizing of the EPA's enforcement authority. EPA should be using science and data to guide its enforcement actions, and there is zero science that backs up homeless pollution as a problem. And it’s wrong to use ePA in this way.”

The former EPA employees in their letter echoed similar criticisms.

“Mr. Wheeler’s actions cannot be treated as legitimate uses of EPA’s authority taken for the purpose of advancing environmental protection, especially considering the current Administration’s record. EPA has not shown much enthusiasm for enforcing environmental laws since President Trump took office, particularly when violations come from big polluters with political connections,” read the letter.