Howard County has fired the laboratory it used to analyze water samples collected from residential wells near Alpha Ridge landfill after the company reported findings that later were proved to be false.
According to county documents released last week, Spectralytix of Gaithersburg told government officials Aug. 11 that the contaminant toluene, a suspected cause of cancer, had been found July 28 in two residential wells near the landfill.
The report, later found to be false, appeared to confirm residents' worst fears, that, contrary to experts' predictions, cancer-causing contaminants found in test wells of the ground water at the landfill had spread to homes beyond the landfill, and with alarming speed.
County officials were not quite so stunned by the report of residential contamination, however, because the county had received false reports from the lab several months earlier. Officials thought the August findings might also be in error and asked the lab to confirm them immediately.
In the meantime, officials were taking no chances. They informed residents of the lab findings, brought each resident 20 gallons of bottled water, took new samples from the wells and told residents they suspected the Spectralytix findings were false.
Evelyn Tomlin, the county environmental manager, said Spectralytix initially told her there was "no problem" when she asked for a confirmation of the report.
Ms. Tomlin asked for a re-analysis after getting the results on Aug. 11. The next day, Spectralytix told her the laboratory had made an error. The re-analysis showed no contaminants in the residential wells.
The error had occurred, the laboratory said, because its testing equipment had not been purged of the residue from heavily contaminated samples from other sources that it had tested earlier.
The laboratory sent Ms. Tomlin two letters Aug. 15 telling her that the county would not be charged for the re-testing and that the Spectralytix project managers were sorry for "any inconvenience this error may have caused."
The county asked Spectralytix and a second laboratory to sample the wells every two days until Aug. 19, when the county fired Spectralytix and signed a temporary contract with a new laboratory.
The county is continuing to conduct "extensive additional tests" of the residential wells with the new laboratory and to take duplicate samples, Ms. Tomlin said. She said the new laboratory will analyze samples until the county awards a new contract though its bidding process.
The county had warned Spectralytix in a May 6 letter that inaccurate tests results could lead to a termination of the lab's contract.