Tonen Chemical Corp. has restarted its 478,000 tpa naphtha cracker about a week earlier than scheduled on September 23, after its planned maintenance. Maintenance at the company's sole cracker in Kawasaki, eastern Japan, began on Aug. 18 and the start-up process commenced late last week. Operations are expected to reach full capacity in one or two days at Tonen Chemical, a petrochemical arm of Tonen General Sekiyu K.K. which is Exxon Mobil's Japan unit.