After years of planning, demolition is finally slated to begin at the controversial Permanente Quarry and cement plant near Cupertino.

The plant halted operations in April 2020 and was slated to permanently close in August 2023 amid pressure from the county. Throughout the plant’s operation, several environmental and governmental agencies filed lawsuits against the quarry for discharging toxic metals and violating water, air and noise pollution standards.

After finding a contractor and getting the required permits, the demolition will begin this month and is slated to be completed by early 2028, according to a release from Heidelberg Materials North America, the multi-national corporation that owns the plant. The contractor will level a total of approximately 40 structures across 123 acres.

“Since we formally announced the permanent closure of the cement kiln in 2022, we have prioritized listening to residents, businesses and other local stakeholders so we could gather input and feedback on how the site could provide value to the community in the long-term,” said David Perkins in the release, Heidelberg Materials senior vice president of sustainability and public affairs. “The commencement of demolition marks a significant step forward in this process.”

Since its purchase by Henry J. Kaiser in 1939, the Permanente Quarry and cement plant contributed to building projects in Northern California, including landmarks such as the Shasta Dam.

The Sierra Club was the first to file a lawsuit in 2011, alleging the quarry was illegally dumping toxic metals into Permanente Creek. Lawsuits from the U.S. Environmental Protection Agency and the State of California followed in 2015. Santa Clara County also found a variety of violations with the plant and issued more than 2,000 citations from 2012 to 2021.

In 2020, the plant’s operations paused due to the COVID-19 pandemic, and amid continued pressure from the county, the quarry and plant closed permanently in 2023. In efforts to restore the area, county officials broke ground on the Permanente Creek Restoration Project in July 2025 to remove toxic mine waste and restore miles of watershed in Cupertino.

Now, the long-awaited demolition of the cement plant begins.

In the release, Cupertino Mayor Kitty Moore said this has been a “long-awaited transition” and an important opportunity for the city to “prioritize the health, safety, and quality of life” for residents.

Santa Clara County Supervisor Margaret Abe-Koga honored the site’s past contribution to the state but said now is the time for change.

“I am looking forward to this important step in the next chapter of the Permanente Quarry and its restoration,” said Abe-Koga in the release. “The Permanente Cement Plant helped build Shasta Dam, powered the efforts in the Pacific theater in WWII and was literally the infrastructural backbone in building much of this valley for 80 years. In its new era, I value Heidelberg Materials’ collaboration and open dialogue as it honors its promises to the public and it embarks on reclaiming the site and restoring Permanente Creek.”

This article was written by Kelcie Lee for Bay City News.