The Abington School District, Jenkintown School District and Cheltenham School District were closed again on Wednesday.
ABINGTON TWP., Pa. (WPVI) -- A four-alarm fire tore through an industrial complex in Abington Township, Pennsylvania on Monday night.
Officials lifted the shelter-in-place and voluntary evacuations at 11 a.m. on Wednesday.
The shelter-in-place order was in effect because of smoke and particulates from the fire, officials said. Residents and businesses in the immediate area near the plant - roughly 700 people - were also asked to voluntarily evacuate late Tuesday afternoon because of concerns over air quality.
A website has also been established by Abington Township, where residents can go to for updates.
The fire broke out around 9:43 p.m. Monday at SPS Technologies, located on the 300 block of Highland Avenue in Montgomery County.
Black smoke could still be seen billowing out of the building Tuesday, more than 13 hours after the first alarm.
The view from Chopper 6 showed flames visible on Tuesday night as crews targeted hot spots.
"There's nothing more important than protecting the members of our community," said Abington Police Chief Patrick Molloy when speaking about the voluntary evacuations that are impacting about 247 homes.
Officials said the building was immediately evacuated and all 60 employees got out safely.
People nearby rushed out of their homes to see what was going on. Some witnesses reported hearing explosions.
Officials said 68 different fire companies in the area responded to the scene.
Aqua, SEPTA, as well as Pennsylvania and federal EPA officials are on site. Departments of public safety from Bucks, Montgomery and Chester counties also responded.
The flames caused explosions and what's inside the industrial complex is of great concern to county officials and residents.
Residence or business within a one-mile radius of the complex were asked to stay inside but that has since been lifted as of 11 a.m. on Wednesday.
That guidance covered around 17,000 residents.
"What's burning, what's in the air? What are we breathing in? How long is this going to go on for?" asked Maria Duffy, from Glenside, who was sheltering in place with her family.
Hazmat crews are continuing to monitor air quality and runoff water in the area. So far, officials say tests have not detected any threats to the public.
"We had concerns that if some of the chemicals were to mix, it could form arsenic which could get in the air and in the smoke that's coming off the fire," said Abington Fire Chief Mike Jones.
"We do know that they use very harsh chemicals in the aeronautical engineering process of making bolts and fasteners. So out of an abundance of caution, we made that decision to self-evacuate," added Chief Molloy.
The City of Philadelphia said they are also monitoring the air quality from the fire event.
"It could be weeks before you see the effect of this type of exposure," explained Dr. Jamie Garfield, a Temple Health pulmonologist.
Two years ago, SPS technologies had to pay a fine of $109,000 to the EPA, for failing to properly dispose of and store hazardous waste, as well as failure to have a clear contingency plan for evacuation.
The Abington School District, Jenkintown School District and Cheltenham School District will be closed again on Wednesday.
Regional rail lines have reopened.
No injuries have been reported, although officials said there are concerns after first responders were exposed to the hazardous materials.
The cause of the fire is still under investigation.
According to its website, SPS Technologies manufactures fasteners and other components for aerospace, transportation, racing, farm and industrial markets.