INTRODUCTION

Pipeline accidents result in fewer fatalities annually than accidents in the other modes of transportation; however, a single pipeline accident has the potential to cause a catastrophic disaster that can injure hundreds of persons, affect thousands more, and cost millions of dollars in terms of property damage, loss of work opportunity, community disruption, ecological damage, and insurance liability. In March 1994, a pipeline accident in Edison, New Jersey, injured 112 persons, destroyed eight buildings, and resulted in the evacuation of 1,500 apartment residents [1]. Accident damage exceeded $25 million. The National Transportation Safety Board s investigation determined that the probable cause.of the accident was excavation damage to the exterior of a 36-inch gas pipe. Less than 3 months later, a gas explosion in Allentown, Pennsylvania, resulted in 1 fatality, 66 injuries, and more than $5 million in property damage [2]. The Safety Board concluded that the accident was caused by a service line that had been exposed during excavation and had subsequently separated at a compression coupling.

A propane gas explosion on November 21, 1996, in the Rio Piedras shopping district of San Juan, Puerto Rico, resulted in 33 fatalities and 69 injuries. This accident, one of the deadliest in pipeline history, made 1996 a record year for pipeline fatalities. The San Juan accident accounted for more fatalities than occurred the entire previous year, and it vividly illustrates the tragic potential of a single excavation damaged pipe.

The Safety Board...