Three-quarters of the cement used in Silicon Valley construction is locally sourced from the Lehigh Cement Company plant and Lehigh Permanente Quarry, tucked away in the unincorporated hills of Santa Clara County. The operation’s contribution to the economy in terms of jobs and materials, however, has been of little comfort to many nearby residents.
Lehigh has been cited by federal, state, and local agencies for a range of environmental problems, including: discharging mercury and benzene into the air; contaminating Permanente Creek with selenium-laced runoff; noisy machinery keeping residential neighbors awake at night; and, clogging the streets with debris-laden trucks.
The company’s May 2019 application to dig a second quarry and substantially expand its mining operations has further heightened tensions between Lehigh and the community.
The 80-year-old plant is the only cement manufacturer in the Bay Area, and Lehigh’s quarry is one of the few in the nation bordering residential neighborhoods. That has always presented challenges.
Adding to the challenge since the quarry became an active mine site more than 100 years ago: Santa Clara County’s population has increased more than 30-fold, narrowing the buffer between heavy industry and civic development.
“You can’t have a use of this magnitude next to a residential community without having issues,” said County Supervisor Joe Simitian, whose district includes the land where Lehigh is located, as well as the neighboring cities of Cupertino, Los Altos, and Los Altos Hills. “Our job is to make sure we stay on top of those issues.”
In addition to its application for a new 60-acre quarry, Lehigh also made headlines recently for the unpermitted transport of materials. In 2018, the County closed a utility road on Lehigh property after discovering that the company was using it without permission to have dozens of loads of mined rock hauled each day to nearby Stevens Creek Quarry for processing.
Instead, the 45-ton trucks began using busy city thoroughfares, escalating public ire at the increased dust, traffic, and noise. In February 2019 the County issued a notice of violation barring Stevens Creek Quarry from receiving, refining, or reselling the aggregate rock.
Over the years the issues involving Lehigh have been many. Reinvigorating impacted aquatic habitat, reducing emissions, and quieting the plant’s nighttime operations took years of County enforcement, community activism, lawsuits, and political will; nevertheless, said Simitian, “There has been real progress.”
After 12 years in the California State Legislature, Simitian returned to the Board of Supervisors in 2013. His first step was to attend to Lehigh, urging monthly site visits by County staff. “If you get out there only two to three times a year, you can’t really tell what’s going on,” he said. “We want to make sure County staff is on top of these issues, and can interact with the public from an informed vantage point.”
Simitian also instituted bi-annual meetings of agency regulators (federal, state, and local), as well as an annual community forum with agency representatives answering questions from the public. For an additional layer of public access, the County posts both the forum videos and answers to any questions not addressed during the meeting on its Lehigh web page.
“There’s an alphabet soup of agencies, and all of these regulators need to meet and give the public reassurance that this operation is doing what it’s supposed to do,” he said. “These meetings are very productive in terms of understanding what’s going on at Lehigh, as well as hearing what the folks I represent care about.”
“No Noise is Good Noise”
For many neighbors, even those who live more than a mile from the facility, the most obvious impact from Lehigh was noise.
“It was a constant humming sound, particularly at night. A single frequency made it especially irritating to the human ear, like a mosquito buzzing, or tinnitus. I couldn’t sleep, my wife and 10-year-old, none of us,” said Amit Butala, who moved to Cupertino a few months before the noise started in 2015. “I’m a radio engineer so I understand sound. And I’m from India, so I’m used to noise pollution. This was different.”
When complaints from sleep-deprived residents continued, Simitian wrote to Lehigh management to stress the importance of voluntary noise mitigation. At the same time, the County stepped up noise monitoring, and in 2016-2017 issued three notices of violation to Lehigh for exceeding its 40-decibel maximum.
Lehigh consultants identified the source of the noise – the fans in the plant’s new emissions stack, which were installed at the behest of the Bay Area Air Quality Management District to improve air quality.
“Connecting the dots illustrates how challenging these issues are,” Simitian said. “Efforts to improve air quality may have had adverse impacts on noise.”
As part of noise-abatement compliance, Lehigh made a variety of improvements to the cement plant including:
- Structural and operational changes to the new stack;
- Installation of insulating blankets and sound suppressors;
- Replacement or removal of 32 fans.
A County noise survey released in 2018 showed a significant reduction in noise decibel levels.
“It’s really made a difference in our lives,” said Christopher Pribe, a software developer who moved to Cupertino’s Oak Valley Development in 1999 with his wife and son. “Before, the sound was constant and penetrating. I wore earplugs, put a pillow on top of my head, and I would still hear it. I was concerned about my family’s mental health. Sleep is so important."
Butala agreed: “I’m so thankful I have a government representative who follows up on issues and is keeping up the pressure. No noise is good noise.”
Additional safeguards to mitigate Lehigh’s environmental and quality-of-life impacts have included:
- Water: A federally mandated $5 million treatment system to protect Permanente Creek habitat was completed in 2017, with oversight from the Bay Area Regional Water Quality Control Board. The system – targeting selenium, a byproduct of quarrying limestone at this site – increased Lehigh’s capacity to treat processing water and storm runoff, and elevated quality to drinking water standards.
- Air: In 2015, working with the Bay Area Air Quality Management District, (BAAQMD) Lehigh consolidated more than 30 smaller, outdated emissions stacks into one taller stack, and installed filters and a dry injection system. While Lehigh Cement ranked eighth for total emissions among top Bay Area industrial sites in 2017, according to the U.S. Environmental Protection Agency, the facility meets the BAAMQD toxic emissions risk reduction rule change to a maximum of 10 parts per million.
- Monitoring: In 2017, the Santa Clara Valley Water district analyzed the previous five years-worth of data from 24 monitoring wells within a four-mile radius of the quarry, and found no evidence of elevated levels of selenium, mercury or arsenic in the drinking water aquifer. In 2015, with the installation of the new stack, BAAMQD began continuous monitoring of emissions. In 2014, at Simitian’s request, the number of Lehigh site visits by County staff increased from a few times a year to monthly.
- Communications: In 2016, the county updated its website with easy access to agency reports and contacts. In 2015, Simitian initiated monthly calls between his office and Lehigh management, to keep the community better informed.
- Site recovery: In 2014, at Simitian’s request, Lehigh restored a lapsed $75,000 assurance bond required by the county as part of the cement plant use permit. (A county-approved reclamation plan requires Lehigh to fill in and re-vegetate the quarry and storage areas when they are no longer in use, in accordance with the state’s Surface Mining and Reclamation
A network of steep terraced roadways up Permanente Ridge leads to a massive circular pit – 650 feet deep, a quarter mile wide. In 1903, the first recorded mining of limestone for use in the sugar beet industry began the evolution of the large quarry that exists today.
The industrialist Henry J. Kaiser located his Permanente Cement Plant at the quarry in 1939. At that time, the land below – known as “The Valley of Heart’s Delight” – was studded with fruit orchards, and many of its cities not yet incorporated. (After World War II, the cement plant and quarry changed hands several times, and are now owned by the multi-national Lehigh Hanson Heidelberg Cement Group.)
While the Lehigh Cement Company powered Silicon Valley’s commercial building boom, its operations also brought scrutiny from environmentalists and the rapidly growing residential population.
In 2011, the Sierra Club sued Lehigh for polluting Permanente Creek. A 2013 settlement required Lehigh to restore 3.5 miles of the creek, build a $5 million water treatment plant, and pay the federal government $2.55 million in civil penalties.
That same year, in a controversial vote, the Santa Clara County Board of Supervisors determined that 2,271 of Lehigh’s 3,510 acres were “vested,” meaning the company could continue mining on those lands without a County use permit.
“The Board of Supervisors has a lot less oversight with the vested property,” said Simitian. “But no matter who was here first, or how a use has been grandfathered in, there are limits, and industry has a responsibility to maintain a safe, clean community.”
Additionally, the Board’s 2012 approval of a reclamation plan amendment, which ensured that the quarry could operate at least through 2037, also proved contentious. Both of the board’s determinations – made while Simitian was in the state legislature – were subject to judicial review.
“The court ruled in the County’s favor,” he said. “But that’s a legal determination,” he noted, “not a determination of whether the Board of Supervisors made a good policy judgement.”
Keeping Lehigh in compliance remains a top priority for Simitian, whose current term runs through 2020. Items on his watch list include: an upcoming state air quality health risk assessment; Permanente Creek habitat restoration; and, Lehigh’s application to develop a second quarry.
A key question will be how much discretion the County has over the new application, given the company’s vested rights: the new mining area falls within the boundary of those vested rights, according to Lehigh.
“This is a significant expansion of the operation and I think there is likely to be a lot of back and forth before the application is even deemed complete,” Simitian said.
Once the new application is complete, the County will prepare an environmental impact report as part of the review process for the application, which is also subject to approval by the County Planning Commission, and appealable to the Board of Supervisors.
“I’ve tried to communicate my view to the quarry and cement plant operators that they’ve got a money machine out there in the hills, and if they want to keep that money machine productive, they need to do a top-flight job of compliance. I would like to think that message sunk in,” Simitian said.
“This is a challenging environmental operation cheek by jowl with a residential setting, and it requires our continued attention,” he added. “We started working on Lehigh my first day in office, and we’ll be working on it on my last day.”