NTSB Safety Recommendation P-04-009

NTSB safety recommendation P-04-009.

The National Transportation Safety Board makes the following safety recommendations to ConocoPhillips Company: Revise your storage tank operating procedures to include instructions for minimizing the possibility of creating a flammable atmosphere and the occurrence of a static discharge inside a tank after a floating roof has been either intentionally or unintentionally landed, especially for tanks where switch loading is likely to occur.

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 policies or procedures. · Switch loading of tanks is not an allowed operating practice at our facilities. If switch loading cannot be avoided due to unanticipated conditions, a specific plan for purging with nitrogen or other inert gas will be followed in accordance with our MOC policy. (Implemented Policy in May, 2004). · Implementation of a Management of Change (MOC) process for emptying tanks and refilling tanks (May 2004) · Verification that loose objects have been removed or secured inside of tank before returning to service after maintenance (May 2003, Section 4.5.2e) · Avoid initial fill during electrical storms · Avoid pumping substantial amounts of air into tank (API 2003 Section 4.5.2f) 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 revised its storage tank operating policies and procedures to minimize the chances of a flammable atmosphere being created and a static discharge occurring inside a tank after the floating roof has landed. Specifically, ConocoPhillips (1) has restricted switch loading at its facilities, and requires a specific safety plan for those times when switch loading can not be avoided due to unanticipated operating conditions, (2) has implemented a management of change process for filling and emptying tanks, (3) requires operators to verify that loose objects have been removed or secured inside a tank before it is returned to service after maintenance, (4) requires that the initial fill of tanks are postponed during electrical storms, and (5) requires that the pumping of substantial amounts of air into a storage tank be avoided wherever possible. Accordingly, because ConocoPhillips has revised its operating procedures as recommended, Safety Recommendation P-04-9 is classified "Closed--Acceptable Action."