Shares in Albright and Wilson, the international chemicals group floated on the London stock market earlier this year, slipped 4p yesterday to 189p after an explosion at one of the company's plants in the Midlands.
The fire services were called to its Oldbury Works site on Wednesday evening but there were no injuries or health risks to local residents, the company said.
It is believed the blast was caused by two incompatible chemicals accidentally mixing in an acid plant. An investigation was immediately ordered.
Albright and Wilson, which used to be part of Tenneco, the US-based industrial company, was floated in February. Its shares were offered at 150p, a lower price than Tenneco had originally expected because of the lack of appetite in the City for new issues.
The company suffered a serious explosion at a plant in Charleston in the US in 1991, resulting in seven deaths and a number of serious injuries.
At the time of the UK flotation, the company said its safety procedures had been significantly improved since then and any legal liabilities arising out of that explosion were fully covered by insurance.
The latest incident is not seen as anything like as serious, since there were no injuries and the plant was within weeks of being decommissioned.