Text For Citation: 02 Item/Group: 001 Hazard: HEAT

Section 5(a)(1) of the Occupational Safety and Health Act of 1970: The employer did not furnish employment and a place of employment which were free from recogn ized hazards that were causing or likely to cause death or serious physical harm in that the method used to clean the 561 main fuel gas line pipes - blowing nat ural gas through them at high velocity - was not implemented in such a way as to protect employees from the hazard of an explosion caused by venting large amoun ts of natural gas into areas where it could accumulate and where, or in close pr oximity to where, ignition sources existed. The following conditions and practic es contributed to the existence of this hazard: the vent pipe configured close t o and below scaffolding, in close proximity to the Power Generation Building, in between two approximately 115 foot tall Heat Recovery Steam Generators (HRSGs) and well below the tops of all of those structures; the failure to eliminate ope n flame ignition sources, including but not limited to propane heaters; construc tion work occurring during the gas blow process; individuals other than those essential to conducting the gas blows working in the area during the gas b low process; and the inability to readily control the amount and pressure of gas flowing through the main gas fuel line. On February 7, 2010, employees were exp osed to serious or fatal impact and other injuries from an explosion hazard crea ted when a large amount of natural gas was blown at high velocity through CT#1 M ain Knockout Drum Vent Pipe (561-TNK-1002) into the area between the two HRSGs a nd close to buildings, scaffolding, partially enclosed work areas, and other str uctures that were adjacent to the Power Generation Building in which employees w orked and in or around which open flame ignition sources, including but not limi ted to propane heaters, existed, construction work was occurring, and numerous e mployees non-essential to conducting the gas blow were working. When natural gas is chosen for this method of cleaning gas line pipes, feasible means of abatement to eliminate or materially reduce the hazard are to ensure th at the vent pipe is positioned vertically and above the Power Generation Buildin g and all other nearby structures, or horizontally to a location away from struc tures that could inhibit the adequate dispersal of the gas; ensure that any and all ignition sources are eliminated; ensure that any and all construction activi ty ceases during the gas blow process; ensure that all workers other than those essential to conducting the gas blows are removed from the building and area aro und which the gas blows are occurring; and ensure the use of devices to control the amount and pressure of gas vented, such as a fast closing pipe shut-off valv e and a gas pressure control valve.