Williamsport, Pa. – The urge to disinfect everything is only natural during a pandemic. But some methods may do more harm than good if not used properly, according the World Health Organization.

Fogging, also known as fumigation or misting, is the spraying of chemicals such as formaldehyde, chlorine-based agents or quaternary ammonium compounds, the WHO said.

In layman's terms, fogging creates a pesticide cloud.

The New Jersey Dept. of Health issued a bulletin warning that four emergency responders were diagnosed with work-related asthma after ambulances were fogged with disinfectants.

"The long-term consequences of converting a disinfectant from liquid to a dry mist (i.e., fogging) are unknown," the New Jersey DOH said. 

The department advises against fogging in ambulances.

Still, several school districts in the Northcentral Pa. region and across the country regularly fog their classrooms and school buses.

The U.S. Environmental Protection Agency warns that pesticides should only be fogged if their product label specifically indicates it. In other words, not just any disinfectant should be poured into a fog machine.

A number of local school districts use fogging as part of their COVID-19 mitigation strategy, including Williamsport, State College, Danville and Sullivan area school districts.

But what are they putting into their machines?

Of the four school districts contacted about their fogging practices, two responded: Danville and State College area school districts.

Danville Area School District Superintendent Dr. Ricki Boyle said the school uses a product called Vital Oxide Disinfectant. 

Vital Oxide is an EPA-approved fogger, according to the company.

"Vital Oxide is one of the few disinfectants that can be dispersed in this manner," the company said on its website.

The district does not fog while students are in the building, Boyle said.

The State College Area School District uses a product called EcoLab, according to Chris Rosenbloom, communications director for the district.

"We've had concerns about different things in our health and safety protocol but the issue of fogging hasn't come up," Rosenbloom said. 

The Williamsport and Sullivan County area school districts did not respond when asked what disinfectant they were using in their fogging machines.