Walter Castro spent months after the Deepwater Horizon oil spill disaster in 2010 measuring air quality along beaches across the Gulf Coast, a task that regularly led him to inhale fumes that reeked of chemicals as he put in long days for weeks at a time.

The 52-year-old Metairie resident claims that contaminated water splashed into his face, exposing him to oil and chemical dispersants that irritated his skin and burned his eyes. On one monitoring mission, he says, he got sick and began shaking violently, and so did the rest of his boat crew.

Castro says in court filings that he requested personal protective equipment, including respirators, but was turned down, and yet was instructed to return to areas where he had measured high levels of benzene, a known carcinogen.

He says he was working for a local subcontractor, Industrial Safety and Health, one of "a multitude of contractors involved in the process" that were ultimately working on behalf of BP.

Years later, Castro was diagnosed with the same chronic conditions for which BP had agreed to compensate response workers — to the tune of a $60,700 payout per worker — as part of a broader medical settlement.

“Even now, I’ll get points where I start feeling nauseous. The sinus, when you wake up you’re feeling the sinus, you’re feeling the pressure, you’re feeling the headaches that come associated with it,” Castro said in an interview. “And it’s almost on occasions that you’ll get the full load of the symptoms that we had back then. They’ll all kick in at the same time.”

Bobby Bradberry, an assistant fire chief in Grand Isle at the time of the spill, can relate. He was among the spill’s first responders, checking oil booms and monitoring the coastline, as well as helping sick clean-up workers as an EMT. He worked on the emergency response and the clean-up for nearly two years, and believes he was exposed to toxic oil fumes and chemicals at all hours of the day.

Coming in contact with contaminated water caused Bradberry’s skin to itch and become irritated, he claims. He said a plane once sprayed him with Corexit, a chemical dispersant BP used in unprecedented quantities to break up the oil. It got in his eyes, he said, and stung worse than mace.

And those medical issues continue for Bradberry, who lives in Metairie. Some days are better than others, he said, but the symptoms are consistent and chronic: burning eyes and sinuses, serious headaches, bronchial spasms, difficulty swallowing.

But what keeps Bradberry, 39, up at night is growing concern that his exposure might lead to something potentially more serious or even fatal, like cancer.

“It constantly runs through my mind, every time I get sick or feel like I’m getting sick,” Bradberry said in an interview. “What’s the doctor going to find? Is this something from that, something that probably could have been prevented?"

Key questions remain

The two men are among a largely forgotten group of clean-up workers and coastal residents who claim exposure to the oil and the chemical dispersants used during BP’s 87-day oil spill made them sick.

Eight years after the Deepwater Horizon drilling rig exploded about 50 miles off the Louisiana coast, killing 11 men and setting off one of the worst environmental disasters in U.S. history, key questions remain about the long-term health impacts of exposure to tens of millions of gallons of crude oil and millions of gallons more of a dispersant used to help make the slick dissipate.

BP was allowed to use that dispersant, Corexit, in unprecedented quantities, even though it has been banned in Britain over human health concerns.

Since 2010, BP has paid tens of billions of dollars’ worth of fines, fees and compensation to individuals, businesses, governments and lawyers because of the disaster. It negotiated a settlement to compensate clean-up workers and coastal residents who said the spill made them sick.

But an estimated 20,000 workers were left out of that deal because their conditions are chronic but weren’t diagnosed by a doctor within two years after the spill. In a class-action settlement BP reached in 2012, they, too, were promised money for skin, eye and breathing ailments, but a later court ruling excluded them from its terms, leaving lawsuits as their only option.

At the same time, BP agreed to a broader multibillion-dollar settlement to compensate Gulf Coast businesses and residents for economic damages due to the spill, and it paid a record $19 billion settlement to the federal government and five Gulf Coast states, including Louisiana, that were impacted by the accident.

By comparison, the medical settlement was inexpensive for BP. It began processing claims in 2013. The deal also provides for comprehensive medical exams every three years for 21 years, and it reserves claimants’ right to file suit against BP for damages if they develop a spill-related medical condition years later.

The money paid out depends on several criteria, such as whether the symptoms affect vision; breathing; ears, nose and throat; skin; the gastrointestinal system; or the heart. Whether the symptoms are short- or long-term, and whether they first appeared or worsened after the spill are also factors.

Under the terms of that deal, workers like Castro and Bradberry who suffer from chronic conditions thought they were eligible for a $60,700 payout.

If the medical settlement had played out the way the plaintiffs expected in 2012, it might have paid out roughly $1.2 billion to 20,000 claimants with chronic conditions specified in the agreement by now. The actual payouts, though, have been a tiny fraction of that amount.

U.S. District Judge Carl Barbier in 2014 — reluctantly, according to his comments from the bench — sided with BP in a dispute that eliminated many plaintiffs with chronic conditions from the settlement.

The settlement defined “later-manifested physical conditions” as any conditions “diagnosed” after April 16, 2012, regardless of when the condition actually appeared, and Barbier's ruling meant that plaintiffs who were diagnosed after that date would have to sue BP and prove their case in court.

Absurd or not?

Lead plaintiffs’ attorney Steve Herman, who helped broker the deal, said the “later-manifested physical conditions” designation was aimed at diseases like cancer and other conditions that take years to show up after exposure.

At an April 2012 court hearing, BP attorney Richard Godfrey said later-manifested physical conditions were “injuries that have not manifested themselves today, that perhaps show up, we hope not, but show up five years from now or 10 years from now.”

In late 2012, Barbier held a "fairness hearing" to determine if the medical settlement was fair to all parties. He heard from people who objected to the deal and from the attorneys for BP and the plaintiffs. The concept of "later-manifested" conditions was discussed, and both BP and the plaintiffs' lawyers told Barbier that term referred to cancer and other illnesses that may not show up for years.

But BP suddenly called for the new interpretation in early 2014, and the medical claims settlement administrator, Matt Garretson of Garretson Resolution Group in Cincinnati, upheld it.

“The parties may have chosen to title the term 'later-manifested physical conditions,' but they defined the term … using the word 'diagnosis,' and we must apply the terms according to their definitions unless the parties agree to amend or the court instructs otherwise,” Garretson told WWL-TV at the time.

Under that view, even claimants who could prove their conditions started with initial exposure were treated as having “later-manifested” illnesses if they failed to get an official doctor’s diagnosis until after April 2012.

In late 2014, Barbier upheld that interpretation. The judge said it was not what was presented to him when he was deciding if the settlement was fair, but that he had no power to overrule the plain meaning of the settlement terms if they did not lead to "absurd" results. "The contract terms," he wrote, "are unambiguous."

Barbier added, "The interpretation may not be what the court envisioned at the time of the fairness hearing ... but the court cannot say the result is absurd.”

But not everyone agrees.

“It’s totally absurd,” said Howard Nations, a Houston attorney representing Castro and Bradberry. “It makes no sense whatsoever.”

Many clean-up and response workers did not make it to a doctor until years after the spill, according to health experts, typically because they lacked insurance or lived too far from a clinic. Without a doctor’s diagnosis of a chronic illness ahead of the April 2012 deadline, the workers were eligible to collect only a $1,300 lump sum payment for acute symptoms suffered after they were first exposed.

“BP pulled the most successful bait-and-switch scam in the history of mass tort litigation, and they’re (BP) definitely to blame for it,” Nations said.

“They were deceived by BP,” he added of the response workers.

But the workers' fortunes could soon change: Castro and Bradberry have both filed lawsuits against BP, and theirs are slated to be among the first medical cases to be tried against the British oil giant at the beginning of next year.

A high legal bar

Garretson has estimated his fees from BP at nearly twice as much as the roughly $67 million in claims he’s approved for roughly 22,840 response workers and others. Only 40 claims have been paid for chronic conditions, and those payments total less than $2.4 million, according to a status report released this month.

Claims turned down by Garretson are sent to BP for a mediation decision, but so far, BP has not elected to mediate a single one, making those claimants eligible to sue BP in federal court.

Nations said his firm represents an estimated 11,000 cleanup workers, mostly from Louisiana. His firm is filing about 20 lawsuits a day in federal court in New Orleans.

Nations claims that the plaintiffs’ lawyers who negotiated the BP settlements badly mismanaged the medical class-action suit, and that they ultimately “rolled over” in favor of BP when the language was reinterpreted because they were more focused on the separate economic class-action case, where nearly all of their clients had claims.

But even as medical lawsuits against BP begin to mount, proving toxic-tort cases in court presents a bigger hurdle than the settlement. It's also unclear whether BP might decide to cut a broader deal to settle the bulk of the claims if verdicts in the first few cases don't go its way, rather than battle each one in court individually.

To prove their case in a toxic-tort lawsuit, lawyers must show that their client’s medical issues were caused by exposure to the toxic substance and not something else, like genetic predisposition or pure chance.

It’s a higher bar than what the settlement required, and trying these cases requires extensive, costly witness testimony, according to Nations, who estimates that the first two cases will cost $200,000 to litigate.

The filing fees alone will cost his firm $4.4 million for 11,000 cases, before a single deposition is taken or expert witness is hired.

“I think we will finally get justice in this case, although it certainly has eluded these people so far,” he said.

But even eight years after the spill, research to determine the potential long-term impact of the exposure faced by cleanup workers is far from complete.

A month into the massive response effort in May 2010, the Environmental Protection Agency gave BP three days to find a less toxic alternative to Corexit, but BP resisted, and the EPA backed off.

Based on witness interviews, the Government Accountability Project, an advocacy group, released a report in 2013 contending that exposure to Corexit could lead to a host of ailments, including abdominal pain, hypertension, kidney and liver damage, memory loss and respiratory problems. The report urged a federal ban on the chemical.

Corexit, which is manufactured by Nalco, is already banned in the United Kingdom because of human health concerns. But BP and clean-up service companies like Clean Gulf Associates still insist that it is “as safe as Dawn dishwashing liquid.”

In court filings, BP has denied allegations that it failed to provide clean-up workers with adequate protective gear and safety training.

'We weren't there'

Since 2010, the National Institute of Environmental Health Sciences has enrolled about 33,000 response workers and Gulf residents in a long-term study that’s being used partly to assess how clean-up work and exposure to oil-related chemicals and dispersants is related to physical symptoms.

Last year, NIEHS reported that workers who were exposed to dispersants while cleaning up after the oil spill experienced a range of symptoms, including coughing and wheezing, and skin and eye irritation.

But many of the study’s participants reported that they no longer experienced the symptoms one to three years later, when the telephone interviews were conducted, although a small percentage of the clean-up workers still had issues.

The research is challenging because it relies on staying in contact with the participants over a long period of time, according to the study’s lead investigator.

“Something is happening, I just don’t know what it is, and it may be that the people who had these jobs that exposed them to dispersants did other things that increase the likelihood of having symptoms,” said Dr. Dale Sandler, the lead investigator in the NIEHS study. “We’re trying to characterize that, but we weren’t there, and the work experience wasn’t that well documented for individual people. It’s not like doing this work in a factory.”