Geçen Temmuz ve Ağustos aylarında güney Bronx’ta 12 kişinin ölümüne neden olan salgından sonra, bu hafta New York’taki 15 soğutma kulesinde tekrar Legionella bakterisi tespit edildi.
The 15 water-cooling towers that were found to be contaminated this week amid a new cluster of Legionnaires’ disease cases had been disinfected less than two months ago, New York City officials said on Thursday, raising questions about how successful the city can be in containing the disease.
After an outbreak of the disease killed 12 people in July and August in the South Bronx, the city required every building with cooling towers, a common source of the Legionella bacteria that cause the disease, to be cleaned within two weeks.
Despite that order, as well as new legislation mandating quarterly inspections of cooling towers, the city found this week that bacteria had regrown in at least 15 towers that had been cleaned recently in the Morris Park section of the Bronx. The testing occurred after a fresh outbreak in that area that has killed one person and sickened at least 12, and spurred an order from health officials for the towers to be disinfected again.
Building owners have complained about the costs of the mandatory cleanings. Disinfection specialists said the bacteria’s quick return was not surprising because the bacteria thrives in warmer weather, and supported the notion that the cleanings were only a short-term fix.
City officials defended their response on Thursday, saying they now have a registry of cooling towers. Legionella bacteria are present throughout the environment, and every year there are about 200 to 300 cases in the city. Before this summer, building owners had never been required to clean their cooling towers regularly.
“The good news is that, unlike in the past, we actually have a handle on where these cooling towers are, and they’ve gotten the kind of cleaning they need,” Mayor Bill de Blasio said in a radio interview on Thursday on the John Gambling Show on WNYM-AM (970).
The infected cooling towers in Morris Park — on buildings including the Bronx Psychiatric Center and Albert Einstein College of Medicine facilities — were discovered after inspectors tested 35 towers in the area this past weekend.
Tim Keane, a consulting engineer at Legionella Risk Management Inc. in Chalfont, Pa., credited the city for an ambitious response to a sprawling problem, and noted that what appears to be an unusual number of recent cases might be partly a result of improved disease tracking. But he said the city erred in not requiring buildings to be tested before the cleanings in August, missing an opportunity to identify towers that might have long-term maintenance problems.
“Nine out of 10 times, the disinfection will be effective,” he said. “But if the treatment program and risk management program isn’t in place after the disinfection, nine out of 10 times the bacteria will regrow again if it was there before.”
The bacteria can return in as little as one or two weeks, he said, and there is still widespread confusion among building owners about how to effectively treat and maintain cooling towers. “They have to react somehow,” Joseph Simboli, a senior account executive for Chemical Specifics Inc. in Maspeth, Queens, said of city health officials. But he added, “This is like hitting a fly with a sledgehammer.”
Christopher Miller, a spokesman for the health department, said “well-maintained and well-looked-after cooling towers are considerably less likely to become sources of the disease.”