BOSTON -- An explosion at a Danvers chemical plant that Gov. Mitt Romney compared to a 2,000-pound bomb sparked a 10-alarm fire Wednesday leveling businesses and damaging homes.

NewsCenter 5's Amalia Barreda reported that help from 30 surrounding cities and towns was brought in for the relief effort. The explosion occurred at CAI Chemical Company at 126 Water St. in Danvers at about 3 a.m.

"It's extraordinary devastation. It's the equivalent of a 2,000-pound being dropped in a residential neighborhood. It's really quite extraordinary," Romney said.

Authorities said that the explosion damaged about 100 nearby homes and an estimated 15 to 25 may eventually have to be torn down. They said an estimated 300 people were at home asleep in the area when the blast occurred. An explosives expert told Romney it was likely many people avoided getting hurt because they were lying down in bed and glass flew over them.

"The fact that these home have been so extraordinarily damaged, but there has been no severe personal injury or death really makes this a Thanksgiving miracle," Romney said.

Danvers Fire Chief James Tutko said crews evacuated 10 injured people who were taken to Salem and Beverly hospitals. He said the "walking wounded" were "in good shape," and no one appeared to have suffered life-threatening injuries. Those who were injured had cuts, bruises and other minor injuries from debris and flying glass, according to hospital officials who said they had treated 11 people.

Environmental officials said immediately following the blaze, there was bright purple water in the White River near the blast site, and state and federal crews were testing for both air and water pollution in the vicinity. Low levels of toluene, a solvent, were found.

"We know that they are volatile organic chemicals. That's what the chemical inventory of this facility was," said Mike Nalipinski of the Environmental Protection Agency. "At this time, those preliminary results show no elevated levels for a broad spectrum of chemicals we're looking at, and we just started doing water sampling."

The company where the blast occurred manufactures water-based and solvent-based inks.

"All of us at CAI are shocked and devastated by this accident. Our foremost concern is for the safety and well-being of our neighbors and employees," CAI said in a statement. "We are so grateful that no serious injuries or fatalities occurred and are doing everything we can to assist officials in determining the cause of the accident, which is unknown at this time."