Businesses have been seen displaying signs that read: “We are closed for deep cleaning.”

But environmental experts said they’re trying to find out if those “deep cleanings’ do more harm than good. Here are some answers about the best way to clean, and why there’s a bigger concern about how people get infected with the coronavirus.

Some health experts said they’re concerned, saying the chemicals used by crews to disinfect businesses may be toxic to people and ineffective. Dr. Jim Diaz, professor of public health and head of environmental and occupational health at LSU Health Sciences Center, agrees.