Western states are in a state of peril as crowded shelters, air pollution, and coughing threaten to increase the number of COVID-19 cases. California, Oregon, and Washington are battling deadly wildfires forcing thousands to seek safety in evacuation shelters without proper protective equipment to contain the coronavirus.

According to The Wall Street Journal, the wildfires are making transmission of the virus easier while making it more difficult for people to protect themselves.

Dr. Peter Chin-Hong, a medical educator specializing in infectious diseases from the University of California at San Francisco, explains that smoke from the virus can irritate the respiratory systems of people with COVID-19 making them cough more often. Smoke damages the lining of the throat in healthy people making it “easier for the virus to land,” he said.

The fires have also made the air quality on the West Coast a health hazard. According to an abstract published in IOP Science, there is a link between hazardous air and COVID-19 rates of mortality in the U.S. The researchers found a 9% increase in deaths when the respiratory hazard index, a measurement of air quality, in the environment increased.

The raging fires are forcing people to stay indoors, often with friends and family, which increases the risk of viral transmission. In Oregon, many people have been placed in hotel rooms, away from others, but healthcare experts say with the immense scope of the fires, there aren’t enough accommodations. Over 2,000 people have been forced to stay at Red Cross shelters in that state, according to the Journal.

While outdoor dining is safer than eating indoors, many experts are encouraging restaurants to now allow patrons to eat inside, away from the smoke and ash. However, this move may also increase the number of COVID-19 cases in the region.

A recent survey presented by the Centers for Disease Control and Prevention (CDC) said that adults who tested positive for COVID-19 were twice as likely as people who tested negative to have reported dining at a restaurant. The CDC said “eating and drinking on-site at locations that offer such options might be important risk factors associated with SARS-CoV-2 infection.”

Emergency visits to hospitals for asthma-like symptoms has doubled since the fires began, increasing the risk of COVID-19 to healthcare workers, according to the Journal. Prior to the wildfires all three states had been making steady progress in lowering the number of cases, and officials said they had plans in place for the start of the fire season. But, according to the Journal, these preparations may not be adequate.

“This is the most severe season we’ve ever had, and we haven’t even gotten into the hearty of it yet,” said Dr. Noemi Doohan, interim public health officer for Mendocino Country.