Thai Prime Minister Yingluck Shinawatra said Sunday she has set up a committee to determine if there was toxic contamination from a deadly plant explosion. Twelve people died and 129 were injured in the blast at Bangkok Synthetics Co.\'s petrochemical factory in the Map Ta Phut area Saturday, the Bangkok Post reported. Yingluck visited some of those injured prior to heading up a meeting of state agencies to discuss the blast. The prime minister was accompanied by Interior Minister Yongyuth Wichaidith and Industry Minister Pongsvas Svasti. The newspaper said there were mounting fears among residents and factory workers over possible air and water contamination by hazardous substances following the explosion. Meanwhile, about 3 miles away the release of a bleaching agent at an Aditya Birla Chemicals Co. plant Sunday evening sent about 50 workers from the factory and a nearby construction site to the hospital with weakness and sore throats, the Post said. The cause of the chemical release was not known.