Surfside, Fla., Mayor Charles Burkett said Monday his city was testing air quality amid health concerns for first responders and local residents after a 12-story oceanfront condominium tower collapsed.

Burkett told CNBC The News with Shepard Smith that preliminary evidence showed the air was not toxic. Those comments came after Burkett said “it’s probably not safe to be here” Friday when asked about air quality.

After meeting an engineer and an air quality specialist, I felt very comfortable breathing in all the smoke and stuff that you and I were breathing all day that day because that was the worst day, ”Burkett said Monday. “I still have a little chest pain from breathing all the smoke.”

Burkett also told host Shepard Smith that the first responders handling the collapse all had protective gear. Last week, Smith asked Burkett if first responders had such equipment after seeing some with no face covering.

Of course, Florida Fire Marshal Jimmy Patronis said in a separate interview Monday that there have been cases where some first responders did not wear face covers. “It can be a little deceiving sometimes when they’re on the pile, when they’re out in the open, when they’re working on moving large debris, there’s a slightly less masked environment,” said Patronis, Smith said.

Almost 370 municipal search and rescue forces work on site. A team from the National Institute of Standards and Technology will study the collapse and identify and preserve materials that could explain what happened. As of Monday night, 150 people were still missing, and at least 11 people were confirmed dead at Surfside.