GTS Legionella Water Testing Lab

Monthly legionella testing of the U.S. Capital
Copyright 1999 The McGraw-Hill Companies, Inc.
Engineering News-Record
May 10, 1999
CAPITOL COOLING TOWERS SUSPECT

THE ARCHITECT OF THE CAPITOL'S OFFICE will resume monthly testing of the water in the Capitol mechanical system's cooling towers to check levels of a bacteria that causes Legionnaire's disease. The action is in response to an April 22 citation from the congressional Office of Compliance for exposing mechanical plant workers to legionella pneumophila.

Last August ''high concentrations'' of legionella were detected in the Capitol utility plant's west cooling towers. The architect's office was also told by the compliance office, which enforces occupational safety and health laws on Capitol Hill, that the east tower's two older wooden units ''were in very poor condition and, until replaced, required intensive maintenance.'' Compliance officials also said that both east and west towers should be ''tested at least monthly'' for legionella unless drained of water.

The disease is spread by inhalation of water vapor. Because the water is in a closed loop system, air in the Capitol itself never picks up contaminated water vapor, says the compliance office. The risk is to workers at the plant and people outside it. To date, no cases of Legionnaire's disease have been reported.

In a statement, the architect's office says it performs quarterly testing in cooler months and weekly testing of the operational towers since warmer weather arrived. After extensive chemical treatment, tests taken ''as recently as April 19, 1999 are negative,'' asserts Herb Franklin, administrative assistant to the architect. Money for the design of replacement cooling towers is in hand, he adds.

The compliance office says results of a March 16 test showed ''a potentially hazardous level'' of legionella and asserts that, for several months prior to March 1999, the architect's office did not test the east towers for legionella and exposed employees to a hazard. To abate the problem, the architect's office is required to conduct monthly culture [GTS recommends epifluorescence microscopy for routine monitoring] tests for the bacteria and provide results for a year. The architect's office says it will comply.