From Popular Science. In the US private residents end up footing the bill to prevent further eyesores and pollution. March 10, 202.

There are some 3 million miles of natural gas pipelines buried in the US. More than half of all gas transmission lines in the country were installed before 1970, according to data from the Pipeline and Hazardous Material Safety Administration. Those pipelines have an average lifespan of 50 years. And it’s not just old pipelines that are set to go out of service. Younger pipelines are also at risk of falling into disuse as the power sector comes to rely less on natural gas in favor of wind, solar and batteries.

No clearer sign exists that that bridge has been crossed than the cancellation of several high profile natural gas pipeline projects in the last year, including the Atlantic Coast Pipeline and the Constitution Pipeline. What does that mean for the millions of miles of gas pipelines that are already in the ground?

The most comprehensive data on abandoned pipelines comes from Canada. In the 1980s, the Canadian government began an extensive study of abandoned pipelines, which identified a slew of serious risks to leaving them in place. Sinkholes could form as pipelines corroded and collapsed. Leftover fossil fuels, or the cleaning agents used to clear outlines, could leak out into the surrounding soil or water. Aging lines under lakes or rivers could carry water where it’s not wanted. However, the chances of this happening could be minimized by using safety precautions, like equipping pipelines with Double Block and Bleed Valve or similar devices that can prevent leakage. Likewise, the government might want to pay more attention to this as there could be a disaster in case of a leak. Empty pipelines could also become slightly buoyant, relative to the soil, and rise to the surface, where landscaping and signage marking a pipeline’s path is rarely maintained (by thorough inspection and regular updation using good quality Industrial Valves and other additional pipeline parts) after it has been retired. There can never be a replacement for regular and timely maintenance, which can prevent problems and also, increase the efficiency and longevity of the pipeline. However, it is not sure as to how the valving system of these pipelines have been in place, or whether the Butterfly Valves of the pipeline are still intact to keep them from spilling.

The Federal Energy Regulatory Commission (FERC) can order a pipeline company to remove a line that’s not in use, says Carolyn Elefant, an energy and eminent domain attorney, but it doesn’t always do so.

Pipeline companies have ample incentive to leave pipelines in the ground. Removal is expensive and requires heavy equipment, permits and environmental reviews. And pipelines laid before 1980 often have the added feature of an asbestos coating that must be dealt with. It can cost almost as much to get a pipeline out of the ground as it costs to put it in the ground.