Primed to Explode

Training and other specific steps can prevent construction fires and explosions, which cause deaths and injuries far too often.

THE explosion at BP's Texas City, Texas, refinery that killed 15 contract construction workers and injured 170 other workers in March 2005 is still reverberating. A lawsuit, an investigation by the Chemical Safety and Hazard Investigation Board (CSB), a glossy safety report from BP (along with $1.6 billion set aside for claims), and a bill in the Texas Legislature to mandate a state occupational safety and health plan were the first wave. But two years after the blast, front-page news coverage of CSB's findings launched a congressional hearing into OSHA's enforcement effectiveness, 60 Minutes broadcast an exposé on one woman's suit against BP, and a tearful rally by relatives of the 15 victims ensured the tragedy would not soon go away.

The sad fact is that deaths and injuries from construction fires and explosions are far too common. While chemical explosions with multiple deaths garner media attention, construction fires and explosions occur on a frustratingly continuous basis. An average of 30 construction workers are killed each year by fires and explosions, according to a study by The Center to Protect Workers’ Rights (CPWR), using data from 1992-2003 of the Census of Fatal Occupational Injuries (CFOI), a Bureau of Labor Statistics research file.
"The reason these [worksite deaths] go unnoticed is that they usually happen one or two fatalities at a time, or the affected workers are contract employees who do not get connected with the proprietary employers," Kim Nibarger, a health and safety specialist with the United Steelworkers (USW), told the House Committee on Education and Labor at the March 22 hearing on the BP disaster and worker safety. USW is the union representing workers at that refinery. "Unfortunately it takes a major event like the one we saw in Texas City for these incidents to get any real notice. In fact, prior to the BP explosion, there was one worker fatality every 16 months for 30 years at the Texas City facility."

Statistics bear out Nibarger's assumptions. While about one in 10 fire or explosion incidents causes multiple deaths, that 10 percent accounts for nearly 25 percent of all of the deaths. Chemical explosions, in particular, are of concern because they are more likely to lead to multiple deaths, with 132 explosions killing 162 construction workers from 1992-2003.

The BP explosion was the worst U.S. workplace disaster in 18 years. The magnitude of that incident helps prove Nibarger's point that drama and media coverage draw attention to the realities of work site deaths. Of course, fires and explosions also cause a multitude of injuries. In 2004, BLS reported 170 explosion injuries and 130 fire injuries involving days away from work in construction. With the BP disaster alone, 170 workers were injured, many with severe burns.

In the CFOI study, construction fires caused about one-quarter of all fatalities, followed by pressurized container explosions (e.g., natural gas pipelines, chemical tanks), and arc flashes and blasts (e.g., electrical panel explosions). More than half (56 percent) of the fires and explosions occurred in industrial workplaces, including construction sites with major renovations (see Table 1). Explosions of pressurized containers in industrial places and premises accounted for 78 percent of all such pressurized explosions.

Table 1. Fire and explosion deaths in construction, by worker activity and location, 1992-2003

Worker activity
Total deaths
Industrial Places
Other Sites*
Driving/operating/riding on vehicles or heavy equipment
Other activities
* Other sites included homes, farms, mines and quarries, places for recreation and sports, streets and highways, public buildings, and residential institutions.
SOURCE: U.S. Department of Labor, Bureau of Labor Statistics CFOI Research File

Worker activities associated with fire and explosion deaths in industrial workplaces included repair and maintenance activities (28 percent), welding (24 percent), driving/operating/riding on heavy equipment (8 percent) and constructing/installing (13 percent). For other locations, worker activities connected with fire and explosion deaths included repair and maintenance activities (18 percent), welding (15 percent), driving/operating/riding on heavy equipment (13 percent), constructing/installing (6 percent), and painting and finishing (13 percent).

Occupations of workers killed in construction fires and explosions included construction laborers (14 percent), welders and cutters (12 percent), electrical workers (9 percent), heavy equipment operators (7 percent), carpenters (7 percent), and supervisors (7 percent).

Causes of Fires and Explosions
With chemical explosions causing approximately half of the fatal fires and explosions between 1992 and 2003, a culprit had to be found. It was welding, accounting for more than one-third of all incidents (see Table 2). The major fuel sources of these explosions were identified as open solvents and fuels, fuel tanks, and chemical tanks or drums.

Welding on chemical tanks/drums and fuel tanks accounted for 26 of the 42 (62 percent) fatal explosions involving these materials. According to CFOI narratives, many of these containers were supposedly empty but had not been purged; welding sparks or flames ignited the residual flammable vapors. Even if a tank or barrel appears empty, trace amounts of many chemicals can spark an explosion. Removing all flammable materials, including grease, tar, acids, or other substances that produce a flammable or toxic vapor when heated, is a must. Other causes of chemical explosions included electrical sparks and mobile construction equipment striking underground gas pipelines.

Welding on "empty" tanks presents a tremendous risk to the work that can be easily eliminated.
The major causes of construction fires were welding, electrical sparks, open flames, and pilot lights, which, taken together, caused 41 of the 83 fatal incidents (49 percent). The fuel sources of fires were open solvent containers or evaporating solvents from surfaces that had just been painted or coated, and vehicles and mobile construction equipment, the latter usually involving highway accidents.

Another cause, often overlooked, is pressurized container explosions. Nearly half (47 percent) of these explosions occurred during repair and/or maintenance. Overpressurization was the single most common reported cause of pressurized container explosions, causing 25 percent of the incidents; 61 percent were of unknown or unmentioned cause. The most common sources of the explosion were exploding vehicle tires (30 percent), where the cause of death was flying wheel rims, and opening pressurized pipes/pipelines (23 percent).
An arc flash calls attention to itself, although these incidents were responsible for the least number of fatalities (40) during the period. Electrical malfunctions and shorts, and contact with energized power lines and other energized wires, made up almost half of the arc flash/blast incidents. Circuit breakers, switchboards, and transformers made up 53 percent of the sources of the arc flashes/blasts.

Table 2. Causes of fatal fire and explosion incidents in construction, 1992-2003

Cause Number of Incidents % of Incidents
Cause Number of Incidents % of Incidents
Chemical Explosions
Welding 48 36
Welding 15
Electrical Sparks 3 10
Electrical Sparks 14
Heavy equipment struck underground pipelines 12 9
Motor vehicle accidents 10
Cutting/drilling 9 7
Open flames/pilot lights 12
Open flames/pilot lights 7 5
Other/unknown 32
Other/unknown 43 33
Total 83
Total 132 100

Cause Number of Incidents % of Incidents
Cause Number of Incidents % of Incidents
Pressurized container explosions

Arc flashes / blasts
Overpressurization 14 35
Electrical malfunction / shorts 7 18
Cutting, drilling, or welding 8 14
Contact with overhead powerlines 6 15
Other / Unknown 35 61
Contact with other energixed wires 6 15
Total 57 100

Other / Unknown

21 53

Total 40 *

* Does not add to 100% due to rounding
SOURCE: U.S. Department of Labor, Bureau of Labor Statistics CFOI Research File

'People Do Not Have to Die'
What can be done to keep construction workers safe? The deaths of 30 construction workers per year from fires and explosions could be substantially reduced if workers are adequately trained and employers and contractors conduct pre-planning before starting a job.

Site-specific training and pre-planning are especially important in industrial plants, where contractor employees are often not aware of the hazards in their temporary working environment. More than half of the construction fire and explosion deaths (202 of 358 deaths, 56 percent)--especially chemical explosions (101 of 161 deaths, 63 percent)--occurred in industrial plants where the employees involved were contract workers. Contract construction employees often are brought into an existing plant to perform projects such as installation of new equipment, renovations, repair and maintenance, and even operation of equipment. Because they often work in an environment new to them, they may not be aware of particular hazards in the plant, which makes adequate planning and site-specific training a must. In addition, owner/contractor contractual relationships and multi-employer contracts that allocate responsibilities can affect the safety of contract construction employees in industrial plants.

One issue requiring further attention is whether existing OSHA regulations are adequate for addressing safety issues for full-time contract workers and whether they are enforced. CSB Chair Carolyn Merritt, appearing before the House committee examining the BP disaster, testified that OSHA's oversight of that refinery was "ineffective." Merritt said CSB's investigation found BP had not followed OSHA's Process Safety Management Standard (29 CFR 1910.119) and OSHA had not adequately inspected the refinery for compliance.
The CSB report contained many criticisms of the lack of safety procedures at the plant, including the location of multiple sources of ignition close to the stack. In the BP explosion, the contractor trailers were located a mere 121 feet from the flare stack that exploded. Merritt, appointed CSB chair by President Bush, was interviewed in the 60 Minutes segment profiling the BP disaster. "The problems that existed at BP Texas City were neither momentary nor superficial," she said. "These things do not have to happen…. They are predictable, and people do not have to die because they're earning a living."

Eva Rowe, who lost both her parents in the refinery blast, talked to 60 Minutes about the disaster and her lawsuit against BP. If victims and survivors settle their suits out of court, "many damaging internal BP documents will remain under court seal," 60 Minutes correspondent Ed Bradley reported. Eva Rowe refuses to settle. "I want everyone to know what [BP] did," Rowe told Bradley. "To BP, my parents were just another number. To them, they're replaceable. To me, they weren't just a number. They're somebody."

Recommendations to Prevent Construction Fires and Explosions

Preventing fires and explosions would be even more effective than preventing other causes of death because nearly one-quarter of fires and explosions in construction are multiple-death incidents. Recommendations for prevention include:
• Adequate training of employees in fire and explosion safety is essential. This is particularly crucial for contract employees in industrial plants, the location of more than half of fire and explosion deaths in construction.
• Conduct Job Hazard Analyses (JHAs) before starting any job to identify and correct high-risk exposures and activities.
• Institute a hot work permit system for welding, which could reduce the number of incidents involving chemical explosions from welding on or in "empty" tanks and fires from welding around solvents. In particular, procedures should ensure that all "empty" tanks and vessels are purged and cleaned before repair or maintenance work to ensure all flammable vapors are removed. Cleaning methods include filling the drum with water, filling the drum with an inert gas such as nitrogen, or purging the drum with steam.
• Open flames or electrical equipment that could emit sparks should not be allowed in areas where solvents are used.
• Maintaining rim wheel tires according to OSHA 1910.177 (servicing multi-piece and single piece rim wheels) could reduce the number of deaths from explosions from overpressurized tires.
• De-energizing live equipment, or isolating or insulating live parts, could decrease the number of arc flashes and explosions.
• Institution of a live-work permit and following NFPA 70E, Standard for Electrical Safety in the Workplace, 2004 edition, could ensure that only qualified electricians work live safely, and only when necessary.

This article originally appeared in the June 2007 issue of Occupational Health & Safety.

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