Coronavirus pandemic

Bacteria in vacant office buildings may pose health threat

NEW YORK • When you finally return to work after the lockdown, the coronavirus might not be the only illness you need to worry about contracting at the office.

Office buildings were emptied out in many cities and states as shelter-in-place orders were issued. Normally in constant use, they have been closed off, and health risks might be accumulating in unseen ways.

"The buildings aren't designed to be left alone for months," said Dr Andrew Whelton, Purdue University associate professor of civil, environmental and ecological engineering.

The professor, other researchers and the public health authorities have issued warnings on the plumbing in buildings, where water may have gone stagnant in pipes, taps and toilets. As lockdowns are lifted, bacteria that build up internally may cause health problems for workers if not addressed. Employees and guests at hotels, gyms and other kinds of buildings could also be at risk.

The biggest worry is Legionella pneumophila. The bacterium can cause Legionnaires' disease, a respiratory condition. It leads to death in about one in 10 cases, said the Centres for Disease Control and Prevention. The National Academies of Science, Engineering, and Medicine estimate that over 52,000 Americans suffer from the disease each year.

A single small outbreak can sicken many. In 2014, a water crisis started in Flint, Michigan, after the city's water source changed and officials failed to inform the public of water quality problems. Many fell ill and the crisis was linked to the deaths of 12 from Legionnaires' disease.

Most worrying, Legionnaires' disease tends to affect people with compromised immune systems.

"Covid patients and survivors could be more vulnerable to this, so when they go back to work we might be concerned about another infection," said Purdue postdoctoral fellow Caitlin Proctor who, along with Dr Whelton, conducted a study that has been accepted for publication in the journal AWWA Water Science examining risks from water stagnation during the coronavirus lockdown.

Legionella, once forming in a building's plumbing, can be dispersed in the air when toilets are flushed. Even turning on taps can send water droplets carrying it into the air.


Typically, facility managers reduce the risk of Legionella and other bacteria by pouring small amounts of disinfectant into water systems. But when water is stagnant for too long, the disinfectant disappears.

Facility staff can also flush out old water and bring in a fresh supply, among other methods.

The researchers say the consequences of long-term water stagnation are relatively unknown. "We haven't really done studies on months-long stagnation," said Dr Proctor. "The ecological system may change. So while we're looking at these organisms, maybe other organisms pop up."


A version of this article appeared in the print edition of The Straits Times on May 22, 2020, with the headline 'Bacteria in vacant office buildings may pose health threat'. Subscribe