Damage to gas and hazardous liquid pipelines from severe flooding totals less than 1 percent of all pipeline accidents.  But that is still far too much, according to the Pipeline and Hazardous Materials Safety Administration (PHMSA).  In a recent safety advisory bulletin, PHMSA notes that water-related pipeline accidents pose a greater threat to drinking water supplies and the environment than accidental releases that do not reach surface water or groundwater. 

The latest advisory bulletin is the sixth that PHMSA has published since 1993 on steps operators should take to reduce the risks to pipelines posed by severe flooding.  While the recommended actions are not new, damage to pipelines from flooding continues to occur.  PHMSA says that three incidents occurred July and August 2011 alone, including a pipeline rupture in Montana that released 63,000 gallons of crude oil into the Yellowstone River.  The rupture was caused by debris washing downstream in the river and damaging the exposed pipeline.

Unsafe conditions must be corrected

Under PHMSA’s Pipeline Safety Regulations (49 CFR 190-199), any operator who discovers any condition that could adversely affect the safe operation of the pipeline system must correct the condition within a reasonable time.  If the condition presents an immediate hazard to persons or property, the operator may not operate the affected segment until the unsafe condition has been corrected.  According to PHMSA, severe flooding is the kind of unusual operating condition that can adversely affect the safe operation of a pipeline and require corrective action.

Enforcement taken

PHMSA’s decision to publish basically the same safety advisory again and again should be a clear sign that the agency is losing patience with operators who do not effectively manage risks from potential flooding.  The consequences for operators who fail to take these steps are getting more severe.  For example, following its investigation of the accident in Montana, PHMSA alleged that the operator failed to properly address known seasonal flooding risks to the safety of its pipeline system, including excessive river scour and erosion, and to implement measures that would have mitigated a spill into a waterway. 

In addition, the agency alleged that the operator failed to establish written procedures for its staff to take prompt and effective action to protect the pipeline from floods and other natural disasters and to minimize the volume of oil released from any section along the pipeline's system, similar to what occurred in the Yellowstone River.  As a result of the alleged violations, PHMSA proposed that the operator pay a $1.7 million penalty.

Vulnerable equipment

According to the bulletin, actions operators should take include evaluating the vulnerability of valves, regulator vents, relief stacks, and other sensitive pipeline equipment to flooding and isolating or extending such equipment above the level of anticipated flooding.  Other actions include training personnel on how to respond rapidly to an accident caused by flooding.  Ongoing surveys to determine if above-water pipelines have become submerged and are subject to being struck by vessels or debris are also essential to managing pipeline safety as well as surveying if scouring of pipeline covers places the segment at higher risk should flooding occur. 

The advisory also lists coordinating actions and provision of information the pipeline operator should undertake with emergency responders, the Coast Guard, contractors, and others involved in postflood restoration, and farmers and other landowners who may be impacted by a release.

Finally, the advisory states that an operator who shuts down a pipeline or reduces operating pressure as a precautionary measure should notify the appropriate PHMSA regional office or state pipeline safety authority before returning the line to service, increasing its operating pressure, or otherwise changing its operating status.

PHMSA’s safety advisory was published in the July 12, 2013, FR.