When we talk about underground storage tanks, we normally talk about how the contents of a leaking UST contaminate surrounding soil and groundwater. This week, however, the Denver Post reported a case of the opposite when soil contaminated with deadly bacteria permeated the walls of one town’s UST. Because the town used the faulty tank to store clean drinking water, hundreds and possibly thousands of town residents became sick.
According to the report, 442 people in the southern Colorado town of Alamosa became violently ill after drinking the city’s tap water, which tests revealed to be positive for a potent strain of the salmonella virus. A survey conducted in the community, however, found that 20 percent of Alamosa’s residents, about 2,000 people, experienced gastrointestinal illness at the time of the salmonella outbreak.
Alamosa, like many small towns throughout the country, draws water for the municipal supply from deep underground aquifers. Water drawn from aquifers is purified by natural processes, thereby eliminating or at least diminishing the need to chlorinate the water.
The process is perfectly safe, unless the clean water is diverted to an underground storage tank containing several holes and cracks, which was the case in Alamosa.
According to health inspectors who examined the tank, farm animals likely defecated on the ground over or near the water tank. As winter snow melted, toxic salmonella bacteria from the feces entered the holes and cracks in the concrete tank.
The salmonella bacteria debilitated many residents of the town, some of whom missed days or weeks of work. Salmonella typically hits younger children and older adults the hardest. In Alamosa, the outbreak is blamed for the death of 55-year-old Larry Velasquez, whose body was already weakened by previous illness.
Although dozens of claims have been filed against the city, many of the city’s residents will have no legal recourse. Colorado state law sets a six-month deadline for filing damage claims against municipalities. The outbreak in Alamosa occurred last year.
Don Koskelin, Alamosa’s public-works director, told the Denver Post that state inspectors who analyzed Alamosa’s water system prior to the outbreak failed to check the underground tank carefully.
“Did he do a detailed inspection of the tank? No, he did not,” Koskelin told the Denver Post.
Colorado’s drinking water program manager, Ron Falco, told the Post that the inspector failed to inspect the tank because a city operator told him that the drinking water system would be replaced in six months.
Alamosa now has a new drinking water distribution system. It also chlorinates all of the tap water.