WASHINGTON (WUSA9) -- A WUSA9/USA TODAY investigation has identified a secret list of risky natural gas pipelines all over the Washington area.
WUSA9 is battling to get it, but gas companies and state regulators are fighting releasing the list to the public.
Our review uncovered the list while researching tens of thousands of miles of aging cast iron and metal pipeline in America's natural gas infrastructure.
About 2,000 miles of the cast iron pipelines are in our area.
- Maryland - 1,378 miles of cast iron pipeline
- Virginia, - 332 miles of cast iron pipeline
- Washington, D.C – 418 miles of cast iron pipeline
Accident investigators and federal regulators have said cast iron pipeline is prone to failure and needs replacing.
Leaks are another problem.
In Washington, documents indicate 3.6% of gas leaks out of D.C. underground pipelines and goes unaccounted.
Across the country, the USA Today/WUSA9 investigation identified natural gas explosions causing as many as 21 deaths a year since 2004, killing a total of 135 people.
About every other day, gas leaks caused property damage or destruction, or people were injured or killed.
84 of those incidents were in Virginia, Maryland, or D.C.
Although there is no way to cross-check the blacked-out high risk addresses, agencies say they are prioritizing high risk sites in accelerated replacement plans.
The plan for replacing all cast iron across the region will take decades.
Story continues below after link to check your zip codes across the country for area specific information.
Although our investigation focuses on older, metal pipes because experts say they are more likely to fail, newer pipes are not immune either.
"Mayday, mayday, man down" can be heard on a fire department video showing a 2009 gas explosion in Forestville, Md.
The Maryland blast involved newer, plastic pipes.
The explosion gutted several Penn Mar Center stores including the pizza shop owned by Mohammed Siddique.
"In the middle of the lunch hour, we see the power outage, then, the gas, gas smell," said Siddique remembering the moments prior to a blast. "At one point we see the roof was boom, out and come down."
Investigation photos show the damage, including where, before that explosion, the rain-wet pavement behind the store was spewing natural gas.
Photographs show an area described in investigative documents as "underground electric line failing," "which resulted in the main gas line melting."
There was no known warning and Ledo's has since rebuilt, but our investigations has uncovered documents showing there are now natural gas warnings, stamped confidential, identifying specific locations in Maryland, Virginia, and D.C. by risk.
"We have an obligation to protect critical infrastructure," Betty Ann Kane, Chairman of the DC Public Service Commission said. "I think anyone would agree, you're not keeping something safe if you're handing out a list where there might be a problem."
Officials say higher risk locations are being prioritized in modernization and replacement projects.
"We have those lists so we can make sure things are getting fixed," Kane said.
Kane refused to disclose the locations citing security concerns and gas company arguments they would reveal proprietary information.
Without the lists, there is no way for the public to tell if any location is near gas mains experts have dubbed "highest project risk" or "riskiest pipe segments."
A marker blacked-out list in DC, obtained under the Freedom of Information Act shows where addresses would be listed, had they not been redacted.
Row after row of Washington gas pipeline with addresses are blacked out and the risk "priority score" also is redacted.
Virginia officials not only redacted the entire service territory map, but cited "confidential information" as the reason for leaving off location identifying attachments that "identify threats" and "rank risk."
Maryland responded "We do not maintain the utility company's DIMP plans"
Unlike the plastic pipes that failed at Ledo Pizza in Forestville, in many cases, experts say the culprit is cast iron or bare steal pipe buried underground.
The USA Today analysis identified tens of thousands of miles of cast iron and bare metal natural gas pipelines. Some 50 or a more than 100 years old…
"The work is going on daily and has been going on for years to replace these pipes," Kane said. "The projects that are going to be done in the first five years are the projects that were identified as the highest risk."
Contributing: John Kelly, USA Today, Kala Kachmar, Montgomery (Ala.) Advertiser; Elizabeth Ganga, The (Westchester County, N.Y.) Journal News; Terri Gruca, KVUE-TV in Austin; Russ Walker and Linda Byron, KING-TV, in Seattle; Rob Johnson, Pensacola (Fla.) News-Journal