A cement plant near Cupertino that provided material for landmark Bay Area structures will remain closed permanently, following an agreement with Santa Clara County.
Hanson Permanente Cement and Lehigh Southwest Cement Company, corporations that own and operate the Lehigh Cement Plant, have signed a deal with the county to ensure the cement kiln at their Permanente Quarry will never restart. The plant has run afoul of environmental regulations thousands of times in the past decade.
Lehigh announced in November it would not restart the kiln that has been shut off since 2020, and the deal makes it legally binding, said District 5 County Supervisor Joe Simitian, whose district includes the quarry and who has led the efforts to strike a deal.
“I’m pleased with this outcome,” Simitian said in a statement. “It protects the community from a change in plans by Lehigh, or new ownership, or simply a new business model.”
Simitian said the language in the agreement is tightly worded, and “guarantees that any and all future owners understand the cement plant is irrevocably closed.”
The cement plant dates back to around 1939, though limestone has been mined from the quarry since the early 1900s. The site sits largely in unincorporated Santa Clara County and parts of Cupertino and Palo Alto.
Cement from the Lehigh site has been used to build major projects around the Bay Area and state, including San Jose Mineta International Airport and the Golden Gate Bridge, Lehigh said.
“We are pleased to formalize our agreement not to restart the kiln at our Permanente cement plant,” Jeff Sieg, a spokesperson for the cement plant, said in an emailed statement. “We remain focused on working collaboratively with the community and other stakeholders on the development of a long-term strategy for the property so that it can continue to provide value in the future.”
The deal came as Lehigh faced mounting pressure from county officials, including the prospect of having operation permits revoked by the county. In negotiations to secure the permanent closure of the cement plant, the county granted Lehigh an 18-month window to work with county staff on revisions to its use permit for the site.
Lehigh came under greater local government scrutiny years after the company in 2019 pushed to expand mining operations at the quarry, including an idea to “chop the top” off the hillside, against a longstanding protection easement.
In January 2022, the Santa Clara County Board of Supervisors called for a comprehensive review of the plant’s environmental violations, from 2012 to 2021.
A May 2022 report revealed more than 2,100 violations, with more than 100 considered serious, while others ranged from minor reporting errors to failed inspections of portions of the company’s diesel truck fleets.
The company was fined more than $12.7 million over that decade for various alleged violations, including the discharging of wastewater into Permanente Creek and excess emissions that worsened air pollution. Most violations and citations stem from the San Francisco Bay Regional Water Quality Control Board, U.S. Mining Safety and Health Administration and Bay Area Air Quality Management Board.
Under a newly submitted application to amend its reclamation plan for the site, Lehigh indicates plans to forego any new mining.
Simitian said this latest agreement helps advance his three main goals for the site to close the cement plant, stop mining in the quarry, and begin the restoration and reclamation of the property. The first two have, for all intents and purposes, been accomplished. But Simitian acknowledged the timeline for shifting the use of the expansive property could be long.
“I think the restoration is probably something that is measured in decades not in years,” Simitian told San José Spotlight. “It’s a 3,500-acre site with a hole in the ground thats been dug over the course of a century, plus all the other activity on the site.”
He noted that Lehigh will likely want to seek the best deal for what remains of their assets and business on the site. The long wind-down process could include continuing production and distribution of crushed rocks from existing supplies, pursuing housing development on the Cupertino portion of the site and possibly allowing other companies to pay a fee to dump clean fill soil in the quarry crater.
He pointed to the former Dumbarton Quarry in Fremont, which was converted to a campground in the East Bay Regional Park District, as a possible model for the Permanente Quarry to follow for restoration.
Julie Hutcheson, the incoming director of environmental advocacy nonprofit Green Foothills, commended the county in a statement for its work on this issue.
“This milestone marks a significant step toward addressing long-standing environmental concerns. We look forward to working together toward the restoration of this landscape for the benefit of people and wildlife,” Hutcheson said.