By MICHAEL RUBINKAM
Last week’s fatal blast at a Pennsylvania chocolate factory highlighted the combustibility of food plants in general and chocolate making in particular. Local, state and federal investigations are ongoing. Pennsylvania State Police have said “everything’s on the table” as fire marshals try to pinpoint the origin and cause. Some workers told relatives they smelled natural gas before the blast, although the gas utility UGI says it received no reports of a gas leak. On Tuesday, federal officials said they were investigating the role of a natural gas pipeline in the explosion. Experts say commercial ovens and furnaces, commercial refrigerant using ammonia and combustible dust are primary explosive hazards at food plants.