Although a fire at a hazardous-waste handling company was dying down Friday afternoon, Apex officials said they want to be sure the threat of contamination has been eliminated before allowing thousands of residents to return home.
Still, officials said late Friday afternoon that residents of the Haddon Hall subdivision could start heading back to their homes.
A leak at the EQ North Carolina plant on Investment Boulevard sent several large plumes of chlorine gas into the air around 9 p.m. Thursday. A large fire broke out at the plant afterward, sending flames more than 100 feet into the night sky and setting off multiple explosions.
EQ is a licensed hazardous-waste facility that repackages and disposes of chemicals for businesses. The exact materials involved in the fire are not known, but the plant handles materials like sulfur, pesticides and chlorine.
"It's really difficult to determine what happened," company spokesman Robert Doyle said. "We've been working with emergency responders, providing any information we can to help."
Twenty-five employees work in the plant, but they had all left by 7 p.m., Doyle said.
WRAL's Melissa Buscher, who was able to get near the plant site Friday morning, said the area smelled like "burned rubber." She also noticed smoldering debris and bent-up metal on Investment Boulevard.
Apex and Wake County officials declared a state of emergency early Friday and evacuated about 17,000 people -- more than half of the town -- within hours.
The evacuation area is bordered by U.S. Highway 1, N.C. Highway 55 and U.S. Highway 64. N.C. 55 was reopened to traffic Friday afternoon after being closed for several hours.
The chemical plume produced by the plant fire had spread across the town overnight, moving as far as the Eva Perry Library, near the intersection of U.S. 64 and Lake Pine Road. But officials said a steady rain Friday morning helped flush the contamination out of the air.
"The prognosis is optimistic as far as clearing the air," Mayor Keith Weatherly said. "The rain is potentially dissipating the particulates in the air."
Air quality sensors have detected no chemical residue in the downtown area, Weatherly said. But he and other officials said they don't want to give residents the all-clear signal until they are sure no contamination risk exists.
"We hope to signal our citizens as soon as possible, but only when it's prudent to do so," he said. "We don't want to give a false expectation."
Residents who live farthest from the plant likely would be allowed to return home first, and authorities would work in from the perimeter of the evacuation zone, he said. There was no timetable for the residents' return.
A hazmat team conducted a preliminary inspection of the plant Friday morning and found that small fires continued to burn inside the collapsed plant, Weatherly said. Team members then did a video inspection, and authorities determined a dry retardant was the best way to extinguish the fire, he said.
Firefighters stayed away from the blaze overnight because the combination of darkness and the chemical cloud made it too dangerous.
"This is the worst possible hazardous materials incident you could have," Town Manager Bruce Radford said.
Apex Fire Chief Mark Haraway said authorities have an inventory of chemicals stored in the plant, but they don't know what is burning inside because the building has collapsed.
State Secretary of Crime Control and Public Safety Bryan Beatty said the rain also increased the chance of contamination on the ground and in the water.
"Runoff of whatever chemicals are there is obviously a concern now," Beatty said, adding that crews are in place to contain the damage and test the quality of nearby water.
Initial tests Friday showed no contamination of any drinking water in the area, officials said.