Legionella in Capitol cooling towers
The citation, dated April 22, was for a “serious” violation of the Occupational Safety and Health Act which occurred at the Capitol Power Plant, the facility which houses the congressional building’s cooling towers. The citation states that “Employees were exposed to the hazard of developing Legionnaire’s disease.”
The document states that high concentrations of legionella were detected in August 1998 in the West Cooling Towers. The Architect of the Capitol was also informed that the aging East Cooling Towers “were in very poor condition and, until replaced, required intensive maintenance.” Because of these conditions, the Office of Compliance mandated monthly testing for the presence of legionella.
However, an inspector took further tests on March 16; results showed “a potentially hazardous level” of legionella in both units of the East Towers. The citation states that for the several months preceding March, the Architect of the Capitol performed no testing.
Clean now?Gary Green, general counsel of the Office of Compliance, added that the West Towers, which had a high level of legionella last August, were clean in March.
The latest tests on the East and West Towers recently came back from the lab and, “As of April, they’re both clean,” he said.
An outside firm has been used to perform the monitoring and maintenance at the power plant.
H.M. Franklin, administrative assistant to the Architect of the Capitol, released a statement asserting that his office was complying with testing requirements.
“In fact,” he noted, “a program of quarterly testing in the cooler months of the year was in place, to be followed by weekly testing of the operational towers as weather warmed.”
Apparently, last year’s program had not been carried out as planned.
Franklin remarked, “After extensive chemical treatments, the results of most tests for legionella were negative in the East Towers.” Tests taken on November 4 and November 7 were negative. Due to the negative tests, a quarterly testing plan was put in place for the winter.
“With the return of warmer weather, weekly testing of operational cooling towers was initiated as originally planned before the issuance of the citation,” commented Franklin. “This program of testing exceeds the frequency recommended in the citation.”
Public riskGreen noted that any contamination of the cooling towers at the power plant, which is located away from the Capitol, could not transmit bacteria to the congressional offices.
However, he acknowledged that, besides exposing plant employees to risk, Washington visitors who are outside in the vicinity of the plant could also be at risk.
Franklin concluded, “The level [of legionella bacteria] that can be causative of disease is a matter of medical disagreement.
“Most outbreaks from cooling towers have been associated with numbers of legionellae well in excess of those concentrations cited by the Office of Compliance, and such concentrations are typically found in warmer months.
“The Architect of the Capitol has adopted a regimen to keep such concentrations as low as practicable.”