Lead contamination at Park City's Five Acre site in Bonanza Park measures nearly 80 times the EPA's safe residential threshold, and the city will have to clean it up without the $2 million federal grant it had hoped for.

Environmental testing conducted for an EPA Brownfields Cleanup Grant application found lead concentrations as high as 15,700 milligrams per kilogram at the city-owned parcel at the southwest corner of Kearns Boulevard and Bonanza Drive, according to a Phase II environmental report posted on the city's website. The EPA's residential soil screening level is 200 milligrams per kilogram.

That's more than twice the worst lead levels dug up at Treasure Mountain Junior High. Arsenic peaked at 528 milligrams per kilogram, compared with 300 at the school site. Every soil sample exceeded the EPA and Summit County's industrial screening level for arsenic of 3 milligrams per kilogram.

The contamination traces to a mine tailings settling pond identified on 1955 U.S. Geological Survey maps adjacent to the Five Acre site, extending beneath what is now the Prospector neighborhood.

Grant denied, cleanup proceeds

Park City sought public comment on its $2 million EPA Brownfields Cleanup Grant application in January 2026, TownLift reported. The city learned it was not selected, but will proceed with remediation using money already in the redevelopment budget. The specific dollar amount budgeted for cleanup has not been publicly disclosed.

"We were disappointed not to be selected, but it does not change our approach," Ryan Blair, Park City's property and environmental services manager, told TownLift on Monday, July 27. "As this site is redeveloped, addressing the contaminated soil will be an integral part of the work."

Blair said the majority of contaminated soil sits in the top six feet. Excavation for the proposed underground parking garage would remove that material during construction. The city plans active dust control, air monitoring, and stormwater runoff controls during the dig, with confirmation sampling afterward.

The work will proceed under Utah's Voluntary Cleanup Program, which provides state oversight and issues a Certificate of Completion upon verified remediation. The same program was used at the Old Town Transit Center and Park City Heights.

What's planned for the site

The Five Acre site is Park City's last large developable parcel. On Thursday, March 19, 2026, the City Council directed partner Brinshore Development to submit applications for Planning Commission review of a mixed-use project including 106 residential units (88 deed-restricted affordable), 32,581 square feet of commercial space, community green space, a child care center, and an underground parking garage, according to the city's project page.

The Planning Commission held a site visit and work session on Wednesday, June 24, and its first public hearing on or around Wednesday, July 8. Mayor Ryan Dickey confirmed at the June 4 Council meeting) that the Council is simultaneously negotiating a development agreement with Brinshore.

Non-compliant under city's own rules

The Five Acre site is one of only a handful of properties still listed as "non-compliant" under Park City's 1988 Soil Ordinance because it has never received a permanent protective soil cover. Blair administers that ordinance, which requires six inches of clean soil or other approved barriers over contaminated ground within mapped areas.

The numbers are stark.

Residents can track the Planning Commission review through the city's Five Acre site project page or attend upcoming public hearings.