Pipeline Accident Report - Propane Gas Explosion Rio Piedras, San Juan, Puerto Rico, November 21, 1996

San Juan, Puerto Rico
November 21, 1996

NTSB Number: PAR-97-01
NTIS Number: PB97-916501
Adopted December 23, 1997
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Executive Summary

About 8:30 a.m. on November 21, 1996, because of a propane gas leak, a commercial building in San Juan, Puerto Rico, exploded. Thirty-three people were killed, and at least 69 were injured.

The building was in Rio Piedras, a shopping district in San Juan. The structure was a sixstory mixture of offices and stores owned by Humberto Vidal, Inc. The company's administrative offices occupied the third, fourth, fifth, and sixth floors, and the first and second floors housed a jewelry store, a record store, and a shoe store.

Probable Cause

The National Transportation Safety Board determines that the probable cause of the propane gas explosion, fueled by an excavation caused gas leak, in the basement of the Humberto Vidal, Inc., office building was the failure of San Juan Gas Company, Inc., (1) to oversee its employees' actions to ensure timely identification and correction of unsafe conditions and strict adherence to operating practices and (2) to provide adequate training to employees. Also contributing to the explosion was (1) the failure of the Research and Special Programs Administration/Office of Pipeline Safety to oversee effectively the pipeline safety program in Puerto Rico, (2) the failure of the Puerto Rico Public Service Commission to require San Juan Gas Company, Inc., to correct identified safety deficiencies, and (3) the failure of Enron Corp. to oversee adequately the operation of San Juan Gas Company, Inc.

Contributing to the loss of life was the failure of San Juan Gas Company, Inc., to inform adequately citizens and businesses of the dangers of propane gas and the safety steps to take when a gas leak is suspected or detected.

In its investigation of this accident, the Safety Board addressed the following safety issues:

  • Adequacy of employee training.
  • Need for an excavation-damage prevention program.
  • Adequacy of maps and records of buried facilities.
  • Adequacy of public education on what to do when the odor of gas is detected.
  • Adequacy of the oversight of the San Juan Gas Company, Inc., from Enron Corp., the Puerto Rico Public Service Commission, and the Office of Pipeline Safety.

As a result of its investigation, the Safety Board issues one safety recommendation to the Secretary of the U.S. Department of Transportation, three to the Research and Special Programs Administration, two to the Puerto Rico Public Service Commission, two to Enron Corp., and one to Heath Consultants, Inc.

As a result of this investigation, the National Transportation Safety Board makes the following recommendations:

To the U.S. Secretary of Transportation:

Improve the Department of Transportation's State pipeline safety evaluation program by developing written guidance and evaluation criteria to assist the Research and Special Programs Administration/Office of Pipeline Safety personnel in objectively evaluating State programs and in requiring States to promptly correct identified program deficiencies. (P-97-5)

To the Research and Special Programs Administration:

Modify your monitoring of State pipeline safety programs to ensure that the States are timely in monitoring the correction of identified safety deficiencies and to ensure that they implement enforcement action as necessary. (P-97-6)

Complete a final rule on employee qualification, training, and testing standards within one year. Require operators to test employees on the safety procedures they are expected to follow and to demonstrate that they can correctly perform the work. (P-97-7)

Require that San Juan Gas Company, Inc., take action necessary to ensure that abandoned pipelines are properly disconnected, purged of propane, and adequately secured to prevent the transmission of flammable vapors and gases, and to ensure that abandoned pipelines are properly identified on maps. (P-97-8)

To the Puerto Rico Public Service Commission:

Develop written procedures to guide pipeline inspectors in assessing the compliance of gas pipeline operators with pipeline safety requirements, in documenting probable violations, in notifying gas pipeline operators of probable violations, and in recommending to the commissioners any formal action that may be required to obtain prompt compliance. (P-97-9).

Require that San Juan Gas Company, Inc., take action necessary to ensure that abandoned pipelines are properly disconnected, purged of propane, and adequately secured to prevent the transmission of flammable vapors and gases, and to ensure that abandoned pipelines are properly identified on maps. (P-97-10)

To Enron Corp.:

Require San Juan Gas Company, Inc., to include procedures in its emergency plan that its employees can use in determining whether a building or area should be evacuated when a gas leak is suspected. (P-97-11).

Require San Juan Gas Company, Inc., when soliciting a training proposal, to require that the proposal include plans for identifying the tasks for which the trainees must be trained and for assessing the job performance of the trainees and the effectiveness of the training. (P-97-12).

To Heath Consultants, Inc.:

Identify, when developing contracted training, the tasks for which the trainees must be trained and develop measures for assessing the job performance of the trainees and the effectiveness of the training. (P-97-13)