Photo courtesy of the National Park Service

It would cost at least $1.4 million to preserve a 132-year-old red-brick coal gasholder building in New Hampshire believed to be the last of its type in the country, according to an engineering analysis. 

The round building with a cupola atop its conical roof was built in Concord in 1888 when coal gas was a major source of light and heat. It was last used in 1953, but its original equipment remains. It holds a floating metal tank that contained up to 120,000 cubic feet (3,398 cubic meters) of coal gas. The tank’s weight provided constant pressure to force the gas out through pipes, where it was distributed to the public. 

The building was named to the National Register of Historic Places in 2018. 

The analysis was done for Liberty Utilities, which owns the building and wants to sell it. The report says removing the building would cost from $500,000 to $700,000, partly because of the need to build a cap to prevent any byproducts from being released from the residue of decades of coal processing, the Concord Monitor reported. 

The report said that repairing the building so that it would remain standing, which it called the “Monument Option,” could cost from $1.47 million to $1.93 million and take half a year. It would cost even more to make it safe for public use. 

The building has seen its share of damage. A tree fell on it in 2014, knocking a large hole in the slate roof. The entryway collapsed in 2016 and had to be removed. There’s also the noticeably tilted cupola, due to the movement of unstable roof rafters and possible storms.