Watson Grinding & Manufacturing Co and Watson Valve Services, Inc. yesterday filed for chapter 11 protection with the U.S. Bankruptcy Court of the Southern District of Texas, KHOU.com reported. The companies stated in a press release that once the court approves their filing it will allow the company to continue operation of its businesses and service to its customers while it works through a plan of reorganization. Watson Grinding & Manufacturing said it ceased operations after a massive propylene gas explosion on Jan. 24. The company also stated it was forced to terminate the employment of approximately 80 workers this week. Watson Valve also had its business near the explosion site and would contract with Watson Grinding to machine products for customers. The company said that it continues to operate at approximately 20 percent of normal capacity by utilizing other suppliers. The preliminary investigation into the deadly explosion at Watson Grinding points toward an accident, according to ATF Special Agent-in-Charge Fred Milanowski. He said that the suspected cause is an electrical spark that ignited a leaking propylene tank.