Hours before first light, David Godines slipped out of the house and headed to work at a railyard near the Houston Ship Channel. Here, he played his bit part in the global petrochemicals trade.

He cleaned the insides of rail tanker cars.

A night breeze drifted in from Galveston Bay and over the railyard. There were many cars to scour.

The cleaners dragged thick drain lines to the tankers' bellies, dropped in steam hoses to loosen hardened gunk that the old-timers called "clabber." Sometimes they climbed inside.

Godines and his crew often were hazy about what chemicals the cars carried - a daily wash list used only a Lubrizol Corp. proprietary code in the column headed "last contained."

What they did know was this: If small gas monitors they wore on their clothes went off, the vapors seeping from the cars could be toxic.

At daybreak, a much louder alarm startled the yard. A voice echoed across the tracks - Man down on east-west. People ran to the tank car at East-11. But they had to step back, their gas monitors buzzing.

"The fumes was so strong," James Ashford Sr., an employee at Austin Industrial Speciality Services, the firm that cleaned cars for Lubrizol, recalled in a deposition.

Godines lay at the bottom of the tanker.

If rivers, rails and roads are the arteries of America's surging petrochemicals industry, tank and barge cleaners are its kidneys, purifying containers so they can return to refineries and to energy and chemical companies across the nation to be refilled. But government health and safety experts don't know much about these cleaners, how many there are or where they're located, a Houston Chronicle investigation has found.

OSHA does not even know how many tank cleaning establishments it has inspected, in part because no standard industry code is used by the U.S. Department of Labor for tracking and inspecting them.

"We have no way to find companies that do tank washing," said Robert McDonough, a compliance officer for the Occupational Safety and Health Administration, in response to a Chronicle request. Officials can't count how many tank and barge cleaners have lost their lives on the job, or how many suffer from nerve damage or cancer related to workplace chemical exposure.

"It's alarming it is so under the radar," said Celeste Monforton, who lectures at the Milken Institute School of Public Health at George Washington University and worked at OSHA. "You are talking about extremely toxic environments. Many of those chemicals have health effects that workers may not experience until 10 to 20 years down the line."

Explore the interactive below map to see where tank cleaning is performed around the country, based on the Houston Chronicle investigation.

The Chronicle identified 373 tank and barge cleaning sites using trade publications, news reports, OSHA records and interviews. There could be many more. Owners of the sites range from individual family-owned facilities like Rainbow Transport Tank Cleaners in Carson, Calif., to Quala, the Florida-headquartered chain of 51 mostly truck wash facilities in 22 states. They stretch across the country, concentrated in Texas and Louisiana, heart of the nation's petrochemical industry. The epicenter: Harris County.

Only a third of the 373 sites have been inspected by OSHA in the past 10 years, the Chronicle determined by searching OSHA inspection reports through the end of 2013.

At those sites OSHA has inspected, the agency found an average of nine dangerous conditions, the records showed. Only a small number had no violations. The most common were allowing cleaners to work without correct breathing protection and allowing them to enter spaces that could be lethally oxygen-deficient.

The Chronicle also used OSHA records, along with news reports, to develop a workplace death toll for this largely hidden industry: 51 direct on-site deaths over the past 15 years, a toll that does not count people who died from work-related diseases that only become apparent days, weeks, months or years later. There could be more.

"It is extremely, extremely hazardous work," says Alan McMillan, a former acting assistant secretary at OSHA and former chief executive officer of the National Safety Council.

Working blind

David Godines' wife, Amy, and their two children were still sleeping when he left for work at the railyard. His life was all about them now.

His childhood friend, Pedro Davila, had remarked on the change, thanking Amy. "You helped my boy out," he said. "You made him into a man."

In a Halloween photo, Godines is fitting his son's tiny toes into a skeleton costume. In another, his daughter is leaning up against her dad, both napping peacefully in the cab of a pickup. So much of that role yet to play.

But Godines would never come home from work.

When a Lubrizol employee dropped a meter into the railcar where Godines lay after the alarm had sounded that morning, it registered "overload," an OSHA inspection report says.

Godines died inside the railcar, where hydrogen sulfide gas was so concentrated that the cells in his lungs stopped exchanging air. Yet experts said his brain would have been alive for a little while, and he would have asphyxiated, sentient.

A wrongful death action brought by Godines' widow raised questions about whether employees recognized the proprietary codes Lubrizol used instead of names to identify chemicals. OSHA investigators had determined that they weren't given the actual names of the chemicals they handled. Workers' knowledge of the chemicals they handle is considered fundamental to industry safety.

In the lawsuit, Godines' co-worker Terry Tyrone Wilson was able to identify some of the codes. "That's a 30-minute wash," he said when quizzed about one, and described another as "a light one." But he couldn't list their basic chemical characteristics.

Austin Industrial and Lubrizol employees later testified in the wrongful death action that they didn't know if key air tests were regularly performed.

Federal rules require that a qualified person with a proper meter test each container to make sure oxygen is sufficient, and it's safe to enter.

But at the yard where Godines worked, the foremen employed a relaxed system in which workers routinely signed each other's names on these entry permits. On the day of Godines' fatal accident, someone else had signed his name.

The lawsuit contains exchanges like this one between Mo Aziz, an attorney representing Amy Robertson Godines, and Wilson, Godines' co-worker, in another instance:

Aziz: Is that your handwriting?

Wilson: No, sir.

Aziz: Where it says "Attendant Signature," is that your signature?

Wilson: No, sir.

Aziz: Do you know who signed this permit on your behalf?

Wilson: No, sir.

Safety procedures changed at the plant after David Godines died.

Lubrizol and Austin Industrial reached a monetary settlement with Amy Godines.

Austin Industrial stressed that it's an employee-owned company for which safety is the pre-eminent value.

"We regret this unfortunate incident and our thoughts and prayers remain with the Godines family," the company said in a statement. "We continue to mandate strict safety procedures and rigorous training programs throughout our company operations."

Lubrizol said it is "absolutely committed to the safety and protection of all employees and external partners who work at our facilities. We regret that this incident occurred at one of our facilities." The company said it remains dedicated to continuous and rigorous improvement in environmental, health, safety and security.

Death without warning

A couple of weeks before Godines' 2011 death, a little way south at Enterprise Products Transportation in Freeport, another young father and tank truck cleaner opened a truck he reportedly believed contained the remains of a safe product. Instead, Chris Shirley was exposed to a mixture of "9 or more chemicals," including "oxirane, amine, oxide, formaldehyde and phthalate" according to OSHA records. He was overcome by the vapors and slid into the belly of the tanker. He was not quite dead when retrieved, but he died at the hospital.

Other casualties track the spread of the American oil patch. In North Dakota last year, two men barely out of high school were cleaning the inside of a crude oil tank truck for the company Plains Trucking. According to federal records, Trevor Davis, 19, lowered his light - not the spark-safe kind that's required - into the tanker to see his work. It blew up. The force blasted a hole through the ceiling. Davis was lifeless when found. His 20-year-old buddy suffered a concussion and head lacerations in the blast.

George Erickson, a seasoned gasoline barge cleaner on the Mobile River in Alabama, had pumped the sludge from the bottom of a long, low tanker barge that carried thousands of gallons of combustible liquid in April 2013.

Vapors rose from the sludge and wafted through the vessel's vents into the wet spring air. Erickson told OSHA that his employer, Oil Recovery Co., did not have an onshore system for sucking up the flammable vapors. Fans were supposed to disperse the fumes. But the blowers failed, government records show, and vapors settled on the surface of the river.

A towboat, Safety Runner, pulled alongside the barge around 9 p.m. Erickson tried frantically to wave the tow away, but the crew couldn't hear him. Within seconds, the vapor sucked into the tug engine's intake. A fireball ripped through the barge and set Erickson on fire. He survived, disfigured, and now struggles to recover with his wife and two children.

A deficient method

These accidents help underscore a common theme: The federal government relies on a deficient method to track and inspect a dangerous industry. Hospitals have an industry code, 622110. Karate camps have an industry code, 611620. It is the way workplace safety records are filed and retrieved in the United States.

But tank and barge wash operations are spread across a remarkable array of industry codes, the Chronicle has found. This is a main reason why OSHA doesn't know where they operate. And it could be why it has inspected only a third of the 373 in the list of tank and barge cleaning sites assembled by the newspaper. The U.S. Coast Guard knows the location of barge cleaners, but its health and safety inspections are limited.

The sites that OSHA did inspect over the past decade fell into 40 different standard industry classification codes. No individual code was good for more than a sixth of the facilities. The most common codes were 488210, Support Activities for Rail Transportation, and 562998, All Other Miscellaneous Waste Management Services.

It's logical that no single code would be apt for these varied businesses. The industry spans water, rail and highway. Companies usually choose the code that best fits their primary business, whereas tank and barge cleaning is often a mere sideline of much larger transport businesses. Shipyards or railyards primarily manufacture or repair cars, not clean them. And companies change over time, even as their codes - which often reflect their initial activity - stay the same.

Still, the lack of a primary industry code haunts the hunt for these dangerous work sites and obscures this little-known, hazardous occupation.

No standard term

The absence of a code also makes it harder to use OSHA's searchable safety records online. There is no standard term used for washing tanks. The word "tank" and "tanker" are not consistently used. The occupation of a worker is described variously as "laborer," "handler," "equipment cleaner" or "unknown," so keyword searches are of limited use.

"One of the things we do a really poor job of is collecting data," said Dean Wingo, who retired recently as assistant administrator for the OSHA region that includes Texas.

Largely unmonitored, tank cleaning is a growing industry. Chemical manufacturing is in a major expansion, thanks to abundant natural gas, from which many chemicals are made. Some of this chemical commerce courses through pipelines. But much goes by barge, by rail and by truck. In 2012, four times as much petroleum traveled in railcars as the year before. Barge traffic is up substantially.

Federal and local safety and health experts who spoke with the Chronicle were sometimes unfamiliar with the conditions that cleaners say they habitually encounter, or with the chemicals they handle. OSHA officials could not provide even a partial list of which tank cleaning establishments have been inspected for compliance with such issues as workers having the right breathing masks and training.

Even in the best circumstances, the agency is hard-pressed to inspect many American workplaces. It prioritizes by responding to accidents, complaints and referrals.

Workers at many of the cleaning sites identified by the Chronicle handle substances that the Environmental Protection Agency categorizes as "hazardous waste." In cleaning the cars, about a third of those 373 sites "generated" 23 million pounds of hazardous waste a year, according to the most recent EPA report. Yet even the sites that handle the most hazardous waste can go uninspected, the Chronicle found.

As hazardous as the tank cleaning business can be, George Erickson, burned by a fireball, and David Godines, asphyxiated in the belly of rail car, are exceptions. In a largely invisible and unregulated industry, most workers aren't killed on the job, or maimed. For pay starting at $14 or $15 an hour, they swing into action with putty knives and squeegees when a driver or pilot pulls into a wash facility.

Vapors in the night

Ramon Quiróz, 47, of Brazoria, first cleaned railroad cars, then tanker trucks. For 11 years, he looked at the metallic inside of various tanks. Inside, he says, first and foremost, it is midnight dark. And hot. Sweat seeps through the seal on your mask into your eyes. "But of course you can't wipe it." That would allow vapors in.

When a hardened chemical coated the tanker walls, which was often, he used a putty knife to scrape the sides.

"But there are still stains in the pores," Quiróz says. "That's when you pull out the steel wool."

Inside the tank, you should not smell the chemical or feel it - that would indicate exposure. But Quiroz says he has had to flee a tank when a substance caused sudden itching all over his body, right through his protective suit.

But in the scope of their daily tasks, workers often lack such a suit, or even a mask. While they drive tanks into and out of the cleaning bays. When they open valves on pressurized tanks, and the vapors hiss out.

Workers are not supposed to be sent into a tank before it has undergone cleaning. But some say they are sent in before any cleaning begins, to remove the leftover chemical waste - known as "heel" - sometimes hundreds of gallons of it.

Quiróz recalls tanks that carried phenols. Exposure to just a tiny amount of these can cause convulsions, collapse and swift death. Breathing phenols burns respiratory tissue and can cause fluid buildup in the lungs. Quiróz, who now works as a pipefitter, says it still bothers him that he was told to vent phenol tankers into the air overnight. The vapor wafted over houses nearby. "You're polluting the people who are sleeping," he said quietly.

The Chronicle found him and a dozen other current and former tank washers at quick marts and truck stops in Texas, in neighborhoods along the Ship Channel, through LinkedIn, and personal ads, in Spanish and English, posted in washaterias.

Mitchell McClelland spent 36 solid years cleaning tanks in Texas. When he moved to Houston from the Piney Woods town of Center, he was newly married, seeking steady work.

The heat inside the tanks, he says, was impressive. Sometimes if a truck driver arrived needing his tanker cleaned in a hurry, then, still piping hot, he'd have to climb inside to final-check for spots.

"You couldn't wear your boots inside the tank because that rubber would kind of melt off and leave a track. You had to get in your sock feet, and I have blistered the bottom of my feet in a tank."

Loved the job

Yet McClelland liked the work. He enjoyed being part of an elite crew sought out by truck drivers hundreds of miles away when they had a tough clean.

In his latter years in the work, some of the white tanks they call sea containers would come back from Asia, hard-baked with solid brown residue.

" 'Cause they can't clean it over there," McClelland says. "They have to come back to us," he said with the evident pride of people who do difficult, essential work.

Terrell Jones left tank cleaning at Qualawash (now called Quala) in Clute, three years ago, after 20 years in the work, his job satisfaction wearing thin. He had prided himself on committing to memory the four-digit chemical codes affixed for safety to trucks and railcars.

"I'd say to the driver, 'You got phosphoric acid in there,' before he even hand me the papers," Jones said. " 'Yep, you right,' and 2554 was acetone. I made it a habit of learning them."

But the increasing use of those oceangoing chemical tanks eventually was one reason Jones left the work behind. The sea containers were sometimes small enough that he couldn't really stand up in them, he said. You had to sit, or work on your knees.

"To me, that was primitive. It made me lose my love for tank cleaning," Jones said.

The risk, he said, didn't seem to be reflected in the pay.

"They are putting the guys in too many tanks and it is just too dangerous," he said. "Tank training definitely needs to be looked into. They would see how dangerous it is."

Michael Bauer, chief executive officer of Quala, said the company provides employees with an anonymous channel apart from their chain of command, called Report It, where they can report circumstances that concern them. It also contracts for third-party safety and environmental audits. "It's part of our culture to stress safety and comprehensive training for every employee from top to bottom," he said.

There is no doubt there have been crucial safety improvements in barge, railcar and tank truck cleaning operations.

Safety experts regard tanks as a subset of what they call confined spaces, where there can be insufficient oxygen to sustain human life. OSHA and employers have worked for years to address the issue of confined spaces, which, as a category, include sewers, tunnels and vaults. Videos and ongoing workplace training provided by professional industrial training companies impress upon workers the dangers of and requirements for entering a confined space. There are clear rules to make the work safe.

Tank washing firms now commonly use harnesses with lifelines to allow workers to be reeled back out of a tank should they fall inside. And someone should always be stationed outside on vigil while a worker is inside.

The National Tank Truck Carriers, a trade group, has a Tank Cleaning and Environmental Council which has helped raise standards for its members, focusing on safety.

Tanks tested constantly

Ann McCulloch, communications director with the American Waterways Operators, which mainly represents barge owners, said those members who do clean barges "conform with and exceed what is required by government regulations."

At FCC Environmental, which provides waste services and operates 38 facilities in the U.S., Clint Mikulencak, vice president for field services, says the air inside tanks is tested continuously. Employees are all fit-tested so they can properly wear respirators.

"As a company we are bound and required not to allow employees to perform a function they don't know how to do. So if we are going to ask them to enter a confined space, you verify everyone is trained for entry, you test the atmosphere and make sure they have the right PPE (personal protective equipment) to make that entry."

Some companies rarely send a worker into a tank.

"There's a real potential for harm," acknowledges Tim Cornish of Veolia Environmental Services, which has pioneered cleaning machines for confined spaces that make "manned entry a thing of the past." But it has no device yet that can fit into trucks and railcars.

"The biggest concern in the industry today is tank entry," acknowledged Bauer, Quala's CEO. "We put a lot of emphasis on that issue. We make sure the employees are trained to do the right thing."

One former Qualawash tank cleaner in Georgia, who has moved on to a career in water treatment, said that in the year and a half he worked with latex and other chemicals, he rarely even had to enter a tank. Javen McCaster said when he did, he was always wearing a protective suit.

"I didn't smell a thing," he says.

Nearly all the cleaners interviewed by the Chronicle mentioned safety improvements over the years.

Yet paradoxically, some also said they feel more at risk. They're under more pressure than ever, they said, to clean more vessels in less time. Some say the number of tanks they're expected to clean per shift is double what it was a few years ago. No one knows how that translates into injury or illness, but the deaths have not stopped.

A single, fatal breath

On Feb. 7, a Kentucky father of three, Eric Young, 37, entered a tanker truck at QC of Kentucky Inc., in Calvert City. He fell unconscious. A co-worker went to help him, and he passed out, too. A third colleague called for help. But Young's life was over.

The truck had contained nitrogen, the coroner determined. Nitrogen is often used to keep already-washed equipment clean and dry. It's a well-known lethal hazard. Since workers cannot see or smell it, and since their first oxygen-free breath can be fatal, there are OSHA rules requiring that every tanker be tested before anyone can go inside.

The president of the company, George Brown, said QC of Kentucky grieves with Young's family and is "evaluating what occurred to take the necessary steps to prevent this type of accident from happening."

"It was a real tragedy, and it's not the first time," said Randy Gray, who was an OSHA compliance officer in Kentucky for a quarter-century and now runs a safety consulting company.

"We've had this happen before," he said, referring to other industry accidents.

On Feb. 5, lighthearted, Kristy Young, Eric's widow, had posted a recipe for chocolate chip cookie cheesecake on her Facebook page. Four days later, her life partner was gone. She was planning a funeral. In the coming weeks, she would take their sons Kalob and Cole to basketballtournaments alone. On April 14, the day their dad would've been 38, the boys chose for him a camouflage cake, in red, orange and green.