Arlington County’s salt storage dome on Old Dominion Road shows so much rust damage that officials say it must be replaced immediately. Neighbors object to the rush and to plans to take down trees to build a temporary structure. (Patricia Sullivan/The Washington Post)

The impending failure of a 90-year-old “salt dome,” which stores most of Arlington County’s winter road salt supply, has triggered a battle between neighbors who want a bigger say in what happens at the site and county officials, who want to replace the aging tank with a temporary fix.

The dome, a 30-foot-high, circular metal storage tank along Old Dominion Drive near Marymount University, can no longer be used because its supporting columns and roof could collapse if the rusted sides fail, engineers told Arlington’s Department of Environmental Services in April.

Time was too short to convene Arlington’s typically extensive community discussions and to survey all the possible alternatives, county officials said. So in early July, they announced an “urgent need” for the salt dome’s replacement.

They proposed putting up a 47-foot-high temporary shelter next to the existing dome, moving the 4,000 tons of salt from one to the other, and demolishing the old dome. To do that, however, the county needed to rezone the 7.5-acre site. As neighbors learned of the plans, they immediately began asking questions.

Why didn’t the county anticipate that rust would eventually damage the metal structure? Why rush through a zoning change that enables the county to put up a temporary building, paving over an adjacent lot with multiple mature trees? Why not use other county-owned lots for the temporary storage while a permanent facility is properly planned?

The situation led to what some residents describe as a break in trust between themselves and the county.

“The current proposed plan shared with the community yesterday is just stunning in its lack of creativity and failure to align to our values,” resident Susan Cunningham told the Arlington County Board in July, when the issue got its first public hearing.

“This is an emergency caused by rust. I know Neil Young says rust never sleeps but it doesn’t move that fast,” added Michael Hogan, president of the Old Dominion Citizens Association.

“On the surface, this sounds like a NIMBY [Not In My Back Yard] issue, but it’s not at all,” Hogan said in a later interview. “We’re happy to be hosts to the services the county needs to provide . . . We’re fine with improving the facilities and adding bathrooms for the drivers.”

County Manager Mark Schwartz acknowledged that the county bungled its handling of the project, expressing regret that staff had not inspected the dome in spring 2017, rushed through its proposals and strained the patience of the community.

The County Board will consider rezoning the property later this month, after the Planning Commission advises it on whether the zoning conforms to the general land-use plan.

“It was a series of bad decisions that led us to this point . . . It was an error and I hope we can come back from it,” County Board Chair Katie Cristol (D) said in an interview last week. “We are moving forward with what is not an optimal plan or an optimal process, but we’re doing so because the alternative is being unprepared for winter weather.”

The dome holds about 60 percent of the road salt reserved for use on icy and snowy streets on the north side of the county. A smaller facility in Shirlington stores salt for the south Arlington streets.

Since the tense July meetings, Department of Environmental Services Director Greg Emanuel said his agency is committed to providing more buffering of nearby homes, saving many of the trees it had originally said would be cut and rezoning as little of the salt dome property as possible. The county is also promising to begin a long-term plan for the site that will probably include a park or recreational space.

Residents say they are still angry about the lack of county follow-through after an extended battle two years ago over the proposed relocation of Fire Station 8. They said they thought they had an agreement with the county to plan a park somewhere on the salt dome site. But efforts to meet with county officials about park planning have gone nowhere, residents said.

That skepticism has colored the current dispute, said Hogan, the neighborhood association president.

“Rezoning is where they lost our trust. They are rezoning more than they need . . . and it never goes from more industrial to less industrial,” he said. “I’ve asked how long is ‘temporary’ and the usual answer is four to five years, but nobody’s willing to write that down . . . This is just a terrible land-use decision.”