NTSB Safety Recommendation P-04-010

NTSB safety recommendation P-04-010.

The National Transportation Safety Board makes the following safety recommendations to ConocoPhillips Company: Evaluate your storage tank operating procedures and make the revisions necessary to ensure that product flow rates in both the tank fill line and the discharge nozzles are restricted to provide a level of protection against excess static electricity that is at least commensurate with industry standards.

Priority: CLASS II

Overall Status: Closed - Acceptable Action

Issued Date: 2004-11-04

Adopted Date: 2004-10-13

Overall Date Closed: 2005-04-27

Synopsis: On April 7, 2003, about 8:55 p.m., central daylight time, an 80,000-barrel storage tank at the ConocoPhillips Glenpool South tank farm in Glenpool, Oklahoma, exploded and burned as it was being filled with diesel. The tank, designated tank 11, had previously contained gasoline, which had been removed from the tank earlier in the day. The tank contained between 7,397 and 7,600 barrels of diesel at the time of the explosion. The resulting fire burned for about 21 hours and damaged two other storage tanks in the area. The cost of the accident, including emergency response, environmental remediation, evacuation, lost product, property damage, and claims, was $2,357,483. There were no injuries or fatalities. Nearby residents were evacuated, and schools were closed for 2 days.

Probable Cause: The National Transportation Safety Board determines that the probable cause of the April 7, 2003, storage tank explosion and fire in Glenpool, Oklahoma, was ignition of a flammable fuel-air mixture within the tank by a static electricity discharge due to the improper manner in which ConocoPhillips Company conducted tank operations. Contributing to the extent of the property damage and the magnitude of the impact on the local community was the failure of American Electric Power employees to recognize the risk the tank fire posed to the nearby power lines and take effective emergency action.

Ntsbnumber: DCA03MP001

Report Number: PAR-04-02

Addressee Name: ConocoPhillips Company

Addressee Status: Closed - Acceptable Action

Addressee Date Closed: 2005-04-27

Addressee Organization Type: P-Private Industry

Communication Date: 2005-02-02

Communication Type: Official Correspondence

Communication Contents: Letter Mail Controlled 2/7/2005 3:09:33 PM MC# 2050046 ConocoPhillips, Pipelines and Terminals Response: The below have been addressed in existing policies and procedures. · Tanks without a floating roof - The tank fill line velocity must be maintained at or below 3.28 feet per second until tank is no longer considered empty, as defined in procedure (API 2003, Section, 4.5.2a) · Tanks with floating roof - The fill line velocity must be maintained at or below 3.28 feet per second until the tank in no longer empty, as defined in the procedure (API 2003, Section 4.5.2b). · Once tank is no longer empty, as per definition, the fill rate may be increased to 23 feet per second (API 2003, Section 4.5.2g) · Credit may not be taken for diffusers -the maximum velocity must be based on the inlet nozzle size where the flow crosses the plane of the tank shell (API 2003, Section 4.5.2b). If your or members of the Safety Board have questions or comments, please feel free to contact Randy Beggs at 580-767-7101 to discuss further. Sincerely: Linus J. Schmitz, Manager, Pipeline Integrity & Reliability

Addressee Organization Type: P-Private Industry

Communication Date: 2005-04-27

Communication Type: Official Correspondence

Communication Contents: The Safety Board notes that ConocoPhillips has evaluated its storage tank operating procedures as requested. Specifically, ConocoPhilips instituted the following policies: (1) for tanks without a floating roof, the tank fill-line velocity must be maintained at or below 3.28 feet per second until tank is no longer considered empty, (2) for tanks with floating roof, the fill-line velocity must be maintained at or below 3.28 feet per second until the tank is no longer empty, (3) when a tank is no longer empty, the fill rate may be increased to 23 feet per second, and (4) credit may not be taken for diffusers, and the maximum velocity must be based on the inlet nozzle size where the flow crosses the plane of the tank shell. Accordingly, because ConocoPhillips has reviewed its operating procedures as requested and implemented revised procedures that should reduce the likelihood of an accident such as the Glenpool from recurring, Safety Recommendation P-04-10 is classified "Closed--Acceptable Action."