Lightning struck two chemical storage tanks at Dow Chemical's Rohm & Haas Bristol plant Wednesday morning, touching off a three-alarm blaze that sent a large orange ball of flame and thick black plume of smoke into the predawn sky and blanketed the area with fumes for hours afterward.

A Bristol Fire Police officer, identified as David Wintz, 65, who was helping direct traffic and went home after complaining about not feeling well, suffered a heart attack and later died at Aria Health-Torresdale Campus, officials said.

No residents had to be evacuated from nearby homes, but the Bristol Borough School District closed its schools because of the fire.

The tanks contained ethyl acrylate and butyl acrylate, both used in the manufacture of a coating product used in paints, according to a statement from Dow.

The fire broke out as powerful thunderstorms moved through the Philadelphia area overnight, downing trees, blocking roads and knocking out power to about 3,500 Peco customers, mostly in Montgomery and Bucks Counties. The Dow statement said lightning struck the tanks about 3:35 a.m. and ignited the blaze.

Firefighters from around the area rushed to the large plant at Routes 413 and State Road, less than a mile from the Burlington-Bristol Bridge. The Bucks County hazardous materials team also responded.

The smoke plume smoke extended high into the sky above the flames as firefighters battled the blaze with water and foam.

The fire appeared to be mostly contained by about 5:30 a.m. and was declared under control about 7:30 a.m. A pungent, burnt-plastic-like odor lingered over the Bristol and Croydon area for hours in the damp air.

Robert Miller, 49, of Linden Street in Bristol, was at the scene when the fire was raging. Miller said he was awakened by a large noise but was unsure if it was thunder or an explosion.

"The minute [the noise] stopped, the fire alarm went off immediately," he said. "The sirens went off like crazy — like I've never heard them before."

Dow said material that escaped from the tanks was contained in a dike surrounding the tanks. "We do not anticipate any health impact to the community," the Dow statement said. Odors, however, "may persist for a few hours until the material is removed from the dike," the company said early in the day.

Early on, the Bucks County Emergency Management and Health Department Offices advised residents that the chemicals can cause minor throat or eye irritation, headaches, and nausea. The vapors had the potential to pose the most problems to those with existing respiratory conditions, such as asthma or emphysema. Local emergency rooms were not reporting any spike in people seeking treatment related to breathing.

By 11:45 a.m., the Bucks County Commissioner's Office had issued a statement saying that the chemical vapors released into the air "were at a minimum," and hazardous materials crews and emergency personnel had been recalled from the scene.

Officials said the air should continue to clear as the day progresses, and residents — who had been advised to stay inside with the doors and windows closed — were being told they could resume normal outdoor activities.