UPDATED -- A new Government Accountability Office report throws cold water on Congressionally mandated plans to further regulate tanker wetlines, to the delight of the nation’s tanker carriers.

The report says the Department of Transportation’s Pipeline and Hazardous Materials Safety Administration’s data cannot be used to reliably identify risks from incidents involving collisions involving tank trucks’ bottom lines or wetlines, because the data has inaccuracies and the agency did not properly examine the costs and benefits of such a rule changes.

“I am extremely pleased with GAO’s findings given its significance to the tank truck industry,” said Daniel R. Furth, president of the National Tank Truck Carriers, in a statement. “As we have mentioned repeatedly, the GAO approached its task in a very professional, thorough manner which led to the same conclusion that we have argued now three times since 1990."

In 2011 PHMSA proposed new rules over requiring that these loading and unloading lines on tankers be absent of any flammable liquids. It was blocked by Congress in last year’s highway funding authorization bill until a study could be completed. 

Based on this study, Furth is uging PHMSA to withdraw this regulations and “allow the carrier and enforcement communities to collectively focus their talents and resources on legitimate safety concerns.”

GAO said the problem is that PHMSA requires carriers to report hazardous material incidents, but the reporting form does not specifically capture wetline incidents. Instead PHMSA officials identify wetline incidents through a process of reviewing carrier-reported incident narratives and other information. GAO found that the narratives do not always clearly indicate whether an incident is wetline related and that information about the consequences of incidents, including fatalities, is not always accurate.

GAO notes PHMSA analyzed the costs and benefits of its proposed 2011 rule to prohibit transportation of flammable liquids in unprotected wetlines, but did not account for uncertainties in its analytical assumptions and limitations in the underlying incident data. For example, PHMSA’s analysis overstated the number of fatalities the proposed rule would prevent when considering actual past incidents and based its cost analysis on the assumption that carriers would install a certain type of wetline purging system, but its limited adoption makes that cost uncertain.

GAO then recommends that PHMSA base any future wetlines rulemaking on the results of this improved data. Additionally, the report recommends changes to the hazmat release reporting process.

NTTC says it efforts were supported by American Trucking Associations, the American Petroleum Institute, the Petroleum Marketers Association of America, and the Truck Trailer Manufacturers Association.

Update adds comments from NTTC.

Related stories:

Tank Carriers Seek Relief from Pending Rules (2011)

Pressure Grows to Prohibit Flammables in Tanker Wet Lines (2009)