Dennis Mason's body was found, face down, between his truck and a crude oil tank at a well site near Kingfisher, Okla. Investigators immediately suspected he was killed by toxic vapors from the oil.

But they weren't able to prove it, because state medical examiners didn't test Mason's blood for petroleum chemicals before declaring his death natural, the result of heart failure.

OSHA inspectors had quickly sent word to the medical examiners that they suspected his death was related to his job hauling oil for Sunoco Logistics Partners. They sent dozens of pages of workplace safety hazard alerts and medical literature recommending tests for industrial chemicals when people die at oil well sites.

But state officials say they never got the email message. Investigators at Oklahoma's Office of the Chief Medical Examiner (OCME) tested only for illegal drugs and alcohol before attributing his death to natural causes.

Mason's family members reject that conclusion. While he may have died from heart failure, they believe state investigators ignored signs his death was related to the oil he was hauling.

Byron Curtis, Oklahoma's chief forensic toxicologist, said the test for alcohol would have detected if there were volatile petroleum chemicals in his blood.

"None of the information we had from the scene or from the postmortem examination indicated we needed to do those tests," he said.

The handling of the case indicates that more than four years after worker safety officials started warning of the lethal dangers of inhaling petroleum gases, the danger is still ignored in some corners of the oil patch.

NIOSH has linked at least 13 oil workers' deaths to inhalation of the petroleum gases such as butane or propane. Safety advocates suspect there may be more cases.

The gases, called volatile hydrocarbons or volatile organic compounds (VOCs), can disrupt the heart and trigger heart failure, especially in people with an existing heart condition or other ailment. The petroleum vapors can push enough oxygen out of the air to asphyxiate a person, even outdoors. In a cruel twist, they disorient the brain so victims often don't try to escape. The vapor clouds can also ignite or explode.

Public health researchers have indicated that the gases could also pose a risk to people who live or work nearby, but they lack data.

The gases whoosh from tank hatches and flow from tanker trucks as they fill. The oil produced from shale using high-volume hydraulic fracturing emits more of the hydrocarbons than conventional crude.

Most of the recorded deaths have occurred on catwalks high off the ground, where workers open "thief" hatches to test and measure oil. More recently, researchers have found that workers are also at risk on the ground from the gases that vent out of truck tanks as drivers fill them with oil.

Safety advocates have been pressing companies since 2014 to reduce workers' exposure to VOCs at well sites, and researchers have urged officials to test for VOCs when investigating deaths of workers found at the sites.

But state officials didn't test for petroleum gases after Roberto Perez, 54, was found dead at an oil well site in West Texas in September 2016 or after Donald Jablonski, 46, died at a North Dakota well site in November 2016. OSHA inspectors found Jablonski wasn't wearing a monitor to detect such gases and his supervisor didn't know how to use one. Both cases, along with Mason's, are listed by NIOSH as suspected petroleum poisoning.

Medical examiners in Oklahoma, a top oil and gas producer, have missed signs of petroleum poisoning before. When oil hauler David Simpson, 57, died in 2014 at a well site outside Ardmore, Okla., they didn't do an autopsy or test for traces of petroleum.

His widow later won a settlement from the owner of the well, XTO Energy Inc., after alleging that the company had failed to protect her husband from the toxic gases.

"We run into some medical examiners and they feel those tests aren't needed," said J.D. Danni, an oil and gas safety and health specialist in OSHA's Denver regional office, who gave a presentation on the hazard at a safety conference in December.

One of the skeptics is Society of Forensic Toxicologists President Dwain Fuller, a Dallas-area practitioner who worked in the oil field as a young man before he became a toxicologist.

"It's mighty unlikely you would die from that in the open air," Fuller said.

OSHA also gets resistance from local officials who don't want to pay for the tests, which can cost around $700. In at least one recent instance, Danni said, OSHA agreed to pay for the test.

Curtis, the Oklahoma toxicologist in the investigation of Mason's death, said he's talked to OSHA officials about their suspicions that workers have been killed by VOCs at well sites. But he remains doubtful.

"They all seem to be of the age where heart attacks are not unusual, though sometimes unanticipated due to undiagnosed heart disease," Curtis told E&E News in an email. "If there was a bunch of 20-year-olds found in similar circumstances, it would be more suspicious to me."

Three of the deaths NIOSH linked to VOCs were men age 21 or younger.

The large companies that own and operate the oil wells often are aware of the hazards and have rules that protect their employees. But the contractors who do much of the work sometimes don't get the same level of protection.

Marathon Oil Corp., which owns the well site where Mason died, declined to comment because Mason's family is suing the company. In court documents, Marathon has denied liability. A spokeswoman for Sunoco Logistics' parent company, Energy Transfer Partners, said the company would not comment on employee matters.

Some companies provide truck drivers with vent hoses to divert the flow of gas away from work sites.

The use of such hoses is recommended in an official standard of the American Petroleum Institute.

Officials at Marathon, the owner of the oil well where Mason died, told OSHA they didn't require vent hoses to be used, but considered it to be a "best practice." The day after Mason died, a Sunoco manager sent a blast text to drivers telling them to use vent hoses at all Marathon wells — "no exceptions."

Source: E&E News