A fire in Indonesia’s Aceh province on Wednesday killed 10 people and injured 40 so far, Reuters reported. The National Disaster Mitigation Agency said firefighters were struggling to contain the blaze.

“We are still collecting data on the number of victims because the fire has not been extinguished,” the agency said in a statement. The agency said dozens of people were being taken to hospital in the provincial capital of Banda Aceh. Gas firm Pertamina is helping with the firefighting operation.

The agency said the fire began after a 250-metre deep well overflowed early on Wednesday and residents gathered to collect the oil.

The head of the police department in Aceh said the well may have been dug illegally. “We suspect this is a well drilled by the community, and that someone was smoking in the area at the time [of the fire],” Wahyu Kuncoro said.

But Sutopo Purwo Nugroho, the spokesperson of the disaster mitigation agency, said the fire may be the result of a spark in a welding pipe, The Jakarta Post reported.