MIDVALE — The Salt Lake Valley's most rapidly growing neighborhood consists largely of a former Superfund site that has shed its toxic status and given way to glossy apartment buildings.
Now known as Bingham Junction, the land once was part of the Midvale Slag site, with smoking smelters that contaminated groundwater and soil with arsenic and lead.
Two years after federal regulators removed the site from its list of toxic areas most in need of environmental cleanup, newly released state data show that the area's population more than doubled in a five-year period.
That's the fastest rate of any U.S. Census-recognized neighborhood across Salt Lake County, and it's boosted by high-density housing, according to the new analysis made public by the Kem C. Gardner Policy Institute.
The report also shows that Salt Lake and Utah counties have continued to expand from 2010 to 2016, with speedy population growth in South Jordan, Herriman and also in fast-developing Vineyard and Point of the Mountain.
"It's a story of growth, and it's a story of change" in the counties that together house roughly half of Utah's population, said Pam Perlich, director of demography.
The estimates consider building permit data and average household sizes to pinpoint growth, expanding on existing Census figures from 2010.
In Midvale, the growth is visible.
The roughly 400-acre Bingham Junction sports several apartment buildings, a Topgolf complex, an expansive park and stores. It's also home to a Utah Transit Authority light-rail stop and Overstock.com's offices, which opened last year.
The redeveloped site makes up much of a U.S. Census tract that also includes a stretch of homes to the south, in Sandy, and to the east, in Midvale. The tract logged the highest percentage of growth, with a total of 9,100 people in 2016, compared to roughly 4,470 in 2010, said Natalie Young, principal analyst for the estimates.
The newcomers are mostly renters.
As of 2016, one-third of new housing belonged to homeowners, while renters were in the majority of homes — just over 2,200. That's the most rental units of any Census-recognized neighborhood in the two counties.
It's been a big adjustment for families who have been in Midvale for generations, said longtime Mayor JoAnn Seghini, who recently retired.
"Many citizens in my community don't believe that high-density housing should ever be in their city. They want single-family homes," Seghini said. But high rises in her community and its neighboring cities are "going to be absolutely critical" as Salt Lake County is expected to surpass 1.7 million residents in the next 50 years, she said.
Seghini said she had concerns "only in the beginning" about building in an area where contaminants remained into the 1980s, both from the smelter and an ore processing mill that left behind 14 million cubic yards of contaminated tailings. The operation closed in 1958.
"We found ways to make sure the contamination would not spread," she said, adding that federal environmental regulators oversaw the $17 million cleanup of the large, metropolitan slag site. The federal Environmental Protection Agency has touted the rebuild as a case study showing that heavily polluted lands can be transformed.
Seghini's city is hoping to make similar progress on a 270-acre swath of land just south of Bingham Junction that also fits in the same Census tract. Development has been cleared for the Jordan Bluffs project where a copper smelter separated metals a century ago.
Even though Seghini's area is growing the most rapidly in terms of percentage, South Jordan gained the most new residents when sheer numbers are considered, at 7,400.10 comments on this story
When Utah County also is considered, the Midvale neighborhood came in third. Vineyard and Lehi had even more rapid growth.
Only one part of the two-county area shrank in population, and that's the Utah State Prison's Draper operation, the demographers found. The number of inmates dropped roughly 20 percent, from 3,840 to 3,089.
Corrections spokeswoman Maria Peterson said the prison population there has declined as facilities for geriatric inmates and other parts of the aging complex have closed and moved. Also at play are prison reforms that have adjusted sentencing and programs for inmates, she said.