KNOXVILLE, Tenn. (AP) — Authorities in eastern Tennessee continued Friday to investigate a container suspected of holding large amounts of dynamite, warning residents that evacuations will likely remain in place throughout the night.

“Until we know more, we implore people to stay out of this area,” Scott Erland, spokesperson for the Knoxville Police Department, told reporters Friday. “We’re still dealing with a volatile situation.”

Residents within 3,000 feet (914 meters) of CMC Recycling — which provides metal recycling services for both residents and industrial clients — have been encouraged to evacuate since Thursday after an employee discovered a 5x5 foot steel box with suspected dynamite.

Erland said the employee was using a torch to open the box and that caused the contents of the box to start smoking, prompting the employee to call authorities. However, it was still unclear what exactly is in the container.

“Until we believe otherwise, we’re going to treat it like it’s going to explode,” he said.

According to police, there’s no evidence of foul play and no evidence that the box was left on site “maliciously.” It’s unknown how long the box had been left at CMC Recycling, but it’s believed to have been there for at least several days, Erland said.

Knoxville’s police department has consulted with the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives, who recommended the immediate area be evacuated.

Knoxville Mayor Indya Kincannon said more than 30 people spent Thursday night in the emergency shelter set up for residents who evacuated. The shelter will remain in place as the investigation continues.

Overall, more than 1,000 people have voluntarily evacuated the area, Erland said.