APEX, N.C. — A hazardous waste site that has seen a chemical fire and a smoking 55-gallon drum in the past two weeks remains a danger, making any cleanup difficult, environmental officials said Thursday.

An Oct. 5 chemical fire at the Environmental Quality Industrial Services facility led to the evacuation of about 17,000 Apex residents. As crews started to clean up the remains of the site, a drum containing a volatile compound reacted with rainwater and ignited, releasing a cloud of smoke.

The state Division of Waste Management immediately stopped the cleanup and asked EQ to submit a report about the incident.

"We're looking at safety issues, the appropriateness of the response, how it matches with the cleanup plan they submitted to us (last week) and we approved," said Cathy Akroyd, a spokeswoman for the state Department of Environment and Natural Resources. "When that is done, we want the cleanup to begin as soon as possible."

Wake County Public Safety Director John Ruckavina said the EQ facility remains a concern.

"At one point in time, these materials were burning," Ruckavina said. "Now, they're not. That still doesn't make them any less hazardous."

The nature of the materials hasn't changed, so the risk won't be gone until the materials are off the site, he said. That is especially true for materials in drums that are dented and burned, he said.

"I'd be reluctant to suggest (the cleanup) would be easy or done in a particular amount of time," Ruckavina said. "You really don't have any way to tell just by looking at it how sensitive it may be."

State officials don't anticipate any further problems at the EQ site, Ackroyd said, but they want to make sure nothing happens.

"We have no reason to suspect any problems, but we do have to hold them to our standards, and that's what we're doing," she said.