The shale boom has brought opportunities for oil and gas haulers. But the boom has also brought a serious problem: an increase in welding accidents.
When welding a tank truck or trailer, safety is paramount. Serious accidents and deaths can occur if a tank or trailer isn’t properly degassed or checked before being serviced.
Just take a look at these examples from the past two years:
- In Williston, N.D., a 28-year-old Marine veteran and welder died from injuries sustained when a cargo tank exploded during welding .
- In Ross, N.D., an employee was killed while working inside a crude oil trailer that exploded when another worker lowered an unapproved light into the space. The second worker received a concussion.
- A worker in Loving, N.M., who was welding a tanker used to haul water and gas, died when the tanker exploded.
- In Bridgeport, Texas, a worker died in an explosion while welding the back of a tanker used to haul water from oil drilling sites.
- In Corona, Calif., one worker died and another was seriously injured when welding a tank truck shell. Federal Motor Carrier Safety Administration investigators said the tank truck had not been cleaned and purged.
- Most recently, four workers in Stillwater, Okla., were injured when a tanker at an oilfield services shop exploded.
Although these tragic incidents have increased in expanding energy regions, such deaths and injuries are not new to the tank truck service and repair industry. From 1998 to 2009, National Tank Truck Carriers recorded 20 deaths and seven injuries involving tank-welding explosions. The growth of oilfield incidents can be attributed to the significant increase in tank truck activity and perhaps to the lack of experience or training in servicing tank truck equipment.
Complacency kills
Although federal regulations require that specification cargo tanks used to haul flammable materials be checked before welding or entry (See 177.854 (g)), many incidents did not involve specification tanks or even flammable loads. A specification cargo tank is not required to transport wastewater containing flammables if the material does not exceed a 140-degree flashpoint (see 173.120 (a)). Products reclassified as combustible do not require a specification tank and those tanks are not subject to Part 180 tests and inspections. However, they can contain explosive vapors.
Workers assume that a nonspecification tank truck or a spec tank that has hauled an oil and water mixture will not explode. That assumption can be deadly. In Florida, three people died when a young worker welded a tire support on a tanker that had hauled oil bottoms. In Maryland, a worker was killed while cutting into an old fuel oil truck being converted to haul water. Fumes that might have been trapped for a long time were enough to ignite and kill.
An experienced worker can check a tanker that has hauled gasoline with an atmospheric tester in less than an hour. Use these safety measures:
- Treat any tanker as if it had hauled gasoline, and conduct tests even if the tank has been steamed and degassed.
- Be sure to check places where vapors can hide, such as hose tubes or voids between compartments.
- Repeat tests if the tanker requires lengthy service, especially on hot days.
- To reduce the chance of vapors gathering into a potentially explosive range, open manhole covers, vapor vents and discharge piping during servicing.
- Use fans to move air in the tanker.
Provide training
Employers must train employees who perform the functions of a hazmat employee (see 172.704 (a) (2)). A safety-conscious employer should provide cargo tank atmospheric testing and proper service procedures to employees who work on any cargo tank that might have hauled petroleum or other flammable products. Atmospheric testing equipment and procedures and employee training records should be checked regularly — if not for the employee, then to show the friendly DOT inspector. Failure to properly train employees is always among the top hazmat violations at cargo tank facilities.
The U.S. Department of Transportation prepared an On Guard Alert in 1997 after the number of deaths and injuries from cargo tank welding incidents increased. Although some of the information is dated, the important message is timeless: “When conducting repair work or testing of these vessels, particular care needs to be given in determining what the tank contains or what it last contained, and ensuring that the tank is sufficiently cleaned and purged of all hazardous materials.”
Let’s end cargo-tank welding deaths and injuries. Don’t trust until you have verified.
IT’S THE LAW: 180.413(a)(2) (2) Prior to each repair, modification, stretching, rebarrelling, or mounting, the cargo tank motor vehicle must be emptied of any hazardous material lading. In addition, cargo tank motor vehicles used to transport flammable or toxic lading must be sufficiently cleaned of residue and purged of vapors so any potential hazard is removed, including void spaces between double bulkheads, piping and vapor recovery systems.
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