Accidents involving tankers laden with liquefied natural gas (LNG), whether intentional or unintentional, will have the most significant impact on public safety and property within a third of a mile from a spill due to thermal hazards, while lesser effects will be felt beyond a mile, even for very large spills, according to a new study by government scientists.

“Risks from accidental LNG spills, such as from collisions and groundings, are small and manageable with current safety policies and practices,” said the Department of Energy’s Sandia National Laboratories in its 167-page study, which was released Tuesday. “Risks from intentional events, such as terrorists acts, can be significantly reduced with appropriate security, planning, prevention and mitigation.”

Vapor clouds could spread over distances of more than a mile from an LNG spill site, and thermal hazards would be felt within a mile of an LNG ship spill, with the greatest hazards generally occurring within a third of a mile of the spill, the report said.

The study is the first federally funded study to take a look at the full consequences of a terrorist attack on an LNG carrier vessel, and includes in its models of plausible consequences actual information from the intelligence community. Sandia acknowledged that information about LNG tanker accidents was scarce, given the industry’s “exemplary safety record, with only eight accidents over the past 40 years.” The majority of the incidents involved tanker groundings. There have been no fatalities.

With the nation hungry for more natural gas, top government leaders are exploring ways to import LNG into the country safely. The push by energy companies to erect LNG terminals has been met with strong opposition from environmentalists and local communities, particularly in the Northeast and on the West Coast.

The results of a federal study on the risks of LNG are “very sobering and…should give everyone reason to make certain that we do not build new LNG facilities in or near a densely populated area,” said Rep. Edward Markey (D-MA).

The Sandia report exposes “serious weaknesses in the way we build these vessels and immense challenges to the public safety community who are tasked with protecting these ships and the terminals they service,” said Markey, who is a member of the House Homeland Security Committee and House Energy and Commerce Committee. He also represents the district where the only urban LNG import terminal in the United States is located.

“Previous studies have assumed that an intentional attack on a loaded LNG tanker might open up a hole no larger than a meter. But Sandia says the intentional hole size ranges up to 12 meters (over 29 feet), with a five-meter hole being their nominal case,” he said. In addition, the study finds that threats could include “‘multiple events and multiple containers damaged,’ which means that even an attack that causes a five-meter hole could lead to a cascade of events that breaches three containers on the ship.”

Sandia noted that the hole sizes were smaller than those used in a number of recent studies. But while smaller, “the breach sizes estimated can still lead to large LNG spills,” it said.

Most terrorist-inflicted damage to an LNG tanker would produce an ignition source and an LNG fire is very likely to occur, along with vapor cloud dispersion, the Sandia study noted.

The Sandia study’s assumptions “vastly increase the estimated consequences of damage” to neighboring facilities and communities compared to other government-funded studies, according to Markey.

In a worst-case scenario, the Sandia study reports “we could see a radius of up to 630 square meters subject to levels of heat and fire that would burn buildings [and] damage steel tanks and machinery, while a radius of up to 2,118 square meters could be exposed to levels of heat that would cause second-degree burns (blistering) within 30 seconds,” Markey noted.

Because the LNG terminal in Everett, MA, which is part of his district, is in such a narrow ship channel, these levels of fire and heat pose a risk to public safety, he said. Markey noted he plans to ask Sandia National Laboratory to apply its findings to the situation in Boston Harbor, “so we can make informed decisions about how best to mitigate the potential safety impacts.

The risk of an accidental LNG spill are the greatest in areas in which LNG shipments “transit narrow harbors or channels, pass under major bridges or over tunnels, or come within 250 meters [less than a third of a mile] of people and major infrastructure elements, such as military facilities, population and commercial centers, or national icons,” the Sandia report said.

Richard Sharples, executive director of The Center for Liquefied Natural Gas, said the group plans to review the study and provide comments to the DOE. He pointed out that “throughout the nearly 40-year history of the LNG operations worldwide and more than 35,000 cargo deliveries, there have been no significant releases of LNG related to a breach or failure of a cargo tank.”

©Copyright 2004 Intelligence Press Inc. All rights reserved. The preceding news report may not be republished or redistributed, in whole or in part, in any form, without prior written consent of Intelligence Press, Inc.