BERKS COUNTY – A federal safety board says a corroded steam pipe and a defective natural gas fitting caused a powerful explosion at a Berks County chocolate factory, killing seven workers when the company failed to evacuate. The National Transportation Safety Board says that the R.M. Palmer Co. failed to have natural gas emergency procedures in place that could have resulted in an immediate evacuation. The 2023 explosion leveled one building and heavily damaged another, causing $42 million in property damage. The safety agency says UGI Corp. was the gas utility that provided service to the candy factory in West Reading.