When the Environmental Protection Agency arrived on the scene of the nation’s largest coal ash spill, the agency was worried about the hundreds of blue-collar laborers already toiling in the toxic stuff without protection, newly reviewed records show.

EPA independent testing of the 5.4 million cubic yards of coal ash that had spilled from a dike at the TVA Kingston Fossil Fuel Power Plant in Roane County in December 2008 was showing alarming levels of radium and arsenic, records show.

Independent researchers from institutions such as Duke University and Wake Forest University also were finding high concentrations of arsenic and radium.

The EPA’s on-site commander was especially worried about the radiation readings. He asked Tetra Tech — an independent environmental testing firm hired by the EPA soon after the spill — to do more testing because he “had concerns about the radium and its effects on the workers,” according to a handwritten Tetra Tech note reviewed by USA TODAY NETWORK - Tennessee.

Coverage:TVA coal ash lawsuits

That note, though, was later crossed out with no explanation. Tetra Tech’s final report made no mention of worker safety concerns, the high radium levels detected by a Ludlum meter or any additional radium testing.

Workers didn't know about radium

Workers — who toiled in the ash without protection — were never told about those results. And, just three months after Tetra Tech and others documented high levels of arsenic and radium in the ash, a new testing firm — this one a contractor working for the Tennessee Valley Authority — insisted the ash was safe, according to an ongoing investigation by USA TODAY NETWORK - Tennessee.

Testing to confirm that claim was later tossed out as invalid because the firm had used a lab with faulty testing methods and equipment, the news organization's investigation shows. More testing was later compromised by intentional tampering, the probe shows.

Now, workers trying to prove the Kingston coal ash is killing them have little defensible testing upon which to rely as a court battle looms later this year that could determine whether the laborers even get a chance to present their case to a jury.

Testing manipulated, abandoned

Nearly a decade after the spill, more than 30 cleanup workers are dead and at least 200 are sick or dying — all with common ailments known to be caused by long-term exposure to arsenic, radium and the host of other toxins and metals found in the ash. The workers are suing Jacobs Engineering — the firm TVA tapped to protect them — in state and federal court.

USA TODAY NETWORK - Tennessee has been investigating the treatment of the hundreds of blue-collar men and women at the cleanup site since early 2017. The news organization in July 2017 published its first series of stories on its investigation.

USA TODAY NETWORK - Tennessee had already discovered evidence, including secret video filmed by workers at the cleanup site, that Jacobs Engineering supervisors lied to laborers about the toxicity of coal ash, refused to provide them protective gear, threatened to fire them if they brought their own, manipulated toxicity test results and abandoned testing for the most dangerous chemicals entirely well before the cleanup effort ended.

Cover up alleged::TVA contractor accused of lying under oath and to workers in Kingston coal ash spill

Follow-up reporting this month has now revealed that Tetra Tech was ordered in early January 2009 to pack up and leave the site as TVA took command and put Jacobs and The Shaw Group in charge.

By May 2009, Jacobs and The Shaw Group were reporting to EPA that testing showed the ash was safe for the workers — despite the high arsenic and radium reported by Tetra Tech and the other independent researchers months earlier.

Jacobs fights against worker safety

The Shaw Group and Jacobs at a May 2009 meeting pushed back against the EPA’s insistence that cleanup workers — who were working seven days a week for 12 to 14 hours each day in the ash — be outfitted with Tyvek suits and respirators. They also argued for higher limits on worker exposure.

“Based on the results of the employee exposure sampling approved through mid February 2009 … the site should not be considered a (hazardous waste) site,” a representative of The Shaw Group Inc. wrote in a May 2009 report.

Harry Pullum of The Shaw Group and Sean Healey of Jacobs insisted any testing standards for dangerous exposure levels should be set high, which meant workers could be exposed to greater levels of toxic chemicals and metals such as arsenic than the EPA said was safe.

EPA caves::EPA bowed to TVA, contractor on worker safety standards at nation's largest coal ash disaster, records say

The plan approved by the EPA soon after that call didn’t require Tyvek suits at all. The EPA-approved plan contained instead strict rules on whether a worker could even qualify for a respirator or a dust mask. It allowed workers to bring their own respirators and masks, but it gave Jacobs final say, with a provision that said the firm could nix such gear if it “created a hazard.”

The EPA also allowed testing that did not focus on arsenic or radium as the leading indicator of dangerous exposure levels for workers — despite the agency’s own conclusion the coal ash at the Kingston site was full of it, records show.

Jacobs’ site safety manager, Tom Bock, and TVA site supervisor Gary McDonald have admitted refusing workers’ requests for respirators and dust masks in violation of the plan’s rules on the approval process.

EPA: Testing methods flawed

Healey later instructed Bock and other Jacobs safety managers to tell workers they could eat a pound of coal ash every day without harm and to downplay to the EPA and the public the need for decontamination stations for workers, according to an October 2009 email. Bock and Healey later denied that in sworn deposition testimony in the workers’ lawsuits.

At the same time Healey was ordering safety managers to downplay the risks of chronic exposure to the toxins in coal ash, The Shaw Group was sending samples of the stuff to Bureau Veritas, another government contractor, to test it, records show.

More than a year later, an EPA audit would show Bureau Veritas’ testing methods were flawed and much of its testing equipment disqualified as “inadequate.” That meant all Bureau Veritas’ testing — which was supposed to monitor worker safety — from September 2009 to January 2010 was tossed out as bad, an EPA report showed.

By then, the EPA had approved — at the insistence of Jacobs and The Shaw Group — a change in the method of testing for danger to workers that relied upon the weight of the ash captured in the monitors for accurate results. It’s known as gravimetric analysis.

The USA TODAY NETWORK - Tennessee has since revealed secret video of ash being dumped from those monitors before they were sent for testing, lowering the weight and skewing the results.

TVA ratepayers paid Jacobs $27.7 million to keep workers and the community safe during the cleanup operation, which spanned five years and cost $1.2 billion overall. TVA ratepayers also may be footing the bill to defend Jacobs Engineering in court, the USA TODAY NETWORK - Tennessee probe revealed.

The workers are paying their own medical and legal bills.