LIVINGSTON, Ky. (AP) — Kentucky officials and crews with rail operator CSX were working Friday to remove train cars and spilled material at the site of a derailment that sparked a chemical fire earlier in the week and prompted home evacuations in a nearby small town.

State officials said Friday they were monitoring the air for traces of hydrogen sulfide and sulfur dioxide, but there had been no detection of those substances at the derailment site or the nearby town of Livingston since Thursday morning. The fire was extinguished at the site just after noon on Thursday.

“We’re now able to get in and begin safely removing cars,” Joe McCann, director of emergency management and hazardous materials for CSX, said at a briefing Friday. McCann said an access road has been built to reach the derailment area and a handful of crashed train cars have been removed.

The CSX train derailed around 2:30 p.m. Wednesday near Livingston, a remote town with about 200 people in Rockcastle County. Residents were encouraged to evacuate just a day before the Thanksgiving holiday.

Two of the 16 cars that derailed carried molten sulfur, which caught fire after the cars were breached. That sulfur is now solidified, according to the state Energy and Environment Cabinet. The Cabinet also has a drone flying over the area Friday to collect information.

The U.S. Environmental Protection Agency is also at the site.

McCann said Thursday that the company had provided hotel rooms to around 100 people and 40 pets. He said that if residents had concerns about returning home after the fire was extinguished they could reach out to the company about extending those arrangements.

CSX said the cause of the derailment and what caused the sulfur to ignite are still under investigation.

Officials said they are also monitoring water quality in the area but a nearby creek is dried up and doesn’t have moving water.