"Seven employes in the metallurgical coke plant of Great Lakes Carbon Corporation, 526 Catalan St., were injured Wednesday morning when gas accumulated at one end of a battery of coke ovens, causing two explosions. The accumulation was caused when a by-pass valve leaked gas into steam that was being used to purge the gas from a gas header line, preparatory to changing an orifice, according to Everett Hart, operations manager of the firm's Missouri Coke and Chemical division."