Lessons From Tank’s Failure

Two months after a massive water tank burst in Westminster, an engineering report has concluded that missing steel bars in the tank contributed to its failure. An executive of the firm that prepared the report says there was no way city officials could have known of the problem. All of this should raise some concern about decisions on where to locate such tanks.

The city-commissioned report says the failure to install “hairline” steel bars and the wrong placement of a reinforcing steel tendon inside the tank allowed the concrete to crack. Water seeping through the cracks over the years corroded metal in the tank, eventually dislodging the walls and sending a six-foot wall of water sweeping down a street and into a townhouse complex and fire station.

City officials said after the accident that the tank had been inspected weekly. Yet, for 30 years after it was built, the lack of the steel bars was never detected. If such a major problem can lurk undiscovered for so long, city officials need to rethink the future siting of such potential threats to public safety. Six people were injured when the 25-foot-tall tank burst.

Building aboveground water tanks so close to residential neighborhoods should not be allowed unless officials can provide better assurances of safety. To their credit, officials of Santa Ana and the Orange County Water District, which each own similar tanks on Bear Street in Santa Ana, are taking precautionary steps that will help reassure nearby residents of the safety of those empty structures.

Those tanks have been empty since before the accident, which displaced more than 30 families. Water officials said they will try to determine whether bars like the ones missing from the Westminster tank are in the ones in Santa Ana. Santa Ana’s water manager said the city wants a structural engineer to certify that the tank is in good shape before it resumes full operation. Such caution is warranted.

Engineers from the Pasadena office of Montgomery Watson, an engineering firm hired by Westminster to investigate the incident, said architectural drawings made after the tank was built in 1967 indicate the “hairline” steel bars were present. However, the firm said it could find no trace of them.

The sleuthing was complicated by the fact that some drawings were missing. That should be a lesson to public agencies of the importance of maintaining good records, a task made easier these days by computers.

Unfortunately for the city, because the tanks were built 30 years ago, the statute of limitations regarding manufacturer liability for such an accident has run out. In any event, the city says neither the manufacturer nor the contractor remains in business.

Damage from the ruptured tank has been estimated at $30 million, much of which is likely to be paid by the city’s insurance. On top of that, building a new tank could cost anywhere from $5 million to $10 million, depending on type and size. That’s a heavy bill for a city struggling like other municipalities to balance its budget.

Officials in all cities should learn from Westminster the need for careful inspection of facilities, whether newly built or repaired. Use of the latest technology, such as powerful X-ray equipment, can help detect faults. Public safety has to be paramount in determining where to put water tanks and other major facilities and in ensuring that they are built to specifications.