UPDATE: Smoldering plastic is to blame for a fourth of july fire at an evansville factory. Investigators say the blaze at lucent polymers started after workers put hot plastic in a cardboard box. The plastic had been removed from a mold, and apparently smoldered in the bottom of the box before igniting. That fire filled the north fulton avenue factory will heavy smoke. ORIGINAL STORY: Evansville Fire Fighters spent the July 4th holiday knocking down a plastics fire on Fulton Avenue. Toxic smoke billowed out of the loading dock doors at Lucent Polymers, 1328 N. Fulton Ave., just after 1 pm Wednesday afternoon. Fire fighters say the blaze began in a bin of plastic parts, and there was no obvious cause. The buildings sprinkler system helped contain the flames, but a lack of windows held most of the smoke inside. Once the smoke cleared fire investigators were able to get a closer look at the scene. Theres still no word on what sparked the fire.