Water Tank Explosion During Routine Cleaning: Yeah, It Can Happen

Police and fire officials said the workers were cleaning a domestic hot-water tank, meaning a tank that provides potable (drinkable) hot water to bathrooms and kitchens. This is routine maintenance, as required by the New York City Department of Health to prevent bacterial growth and other hazards. It was anything but routine, however, when, as a Fire Department spokesperson told T he New York Times , a "little bit of an explosion and a flash fire" occurred at 9:44 a.m. in a 22nd-floor mechanical room when a worker turned on a halogen lamp while another was cleaning the tank with alcohol. The heat of the lamp ignited flammable vapors from the cleaning solution.

How could such a basic blunder happen?

Tragedy and Training

"The explosion at Columbia was caused by, going by reports, untrained people who used a flammable object in a confined space with a halogen lamp," observes Richard Silver, president of the tank-cleaning company American Pipe & Tank. "It's like turning a gas jet on in your kitchen and 10 minutes later walking in and lighting a match."

"Who knows how people get contracts?" wonders Abe Seeman, senior account manager of the tank-cleaning firm The Metro Group — which, like American Pipe & Tank and most other such companies, uses a disinfecting solution of sodium hypochlorite (e.g. bleach) or calcium hypochlorite (e.g. bleaching powder). "With an alcohol-based solution, the likelihood of getting a flammable vapor is much more likely," Seeman says. Vapors can arise from sodium hypochlorite as well, he notes," but that's not nearly as flammable and dangerous as an alcohol-based solution."

Acid Waste Management, which does not have a website but has telephone listings for offices in Elmsford, New Rochelle and Mount Vernon, N.Y., did not respond to calls or e-mails.

How can your building avoid this particular fate? Start by ensuring that a company's workers are either licensed master plumbers or that the company holds a valid permit issued by the Health Commissioner, as per Article 141 of the New York City Health Code.

"The City of New York is very specific in that anyone who enters any water tank that is used for potable water has to be either licensed as a New York City master plumber or have certification from the Dept. of Health," says Silver. "Optimally, they should have both."

Have OSHA's OK

As well, he suggests, you should ask and ensure that workers are certified as meeting OSHA (Occupational Safety and Health Administration) standards for working in "confined spaces." OSHA-certified trainers come to tank-cleaning companies such as his, Silver says, to train workers. In fact, he adds, "In many instances an insurance carrier who represents the individual firm will send instructors" as a matter of course.

"There should not have been anyone there who was not trained," says Seeman. Both he and Silver also say that the workers themselves should wear personal protection equipment such as goggles, gloves, hard hats and steel-toed shoes. If you notice workers around your water tank without such protection, that's a red flag that the company you've hired doesn't take safety seriously.

As for having light in the confined space, "A flashlight or a safety helmet with a battery-powered light — that's it," says Seeman. "You should never have a need for a halogen lamp. You should always have a need for a little common sense."