Post Public 2021 Meeting Questions Answered


    Yes, Lehigh does emit CO2.  CO2 is emitted from the burning of fossil fuels (petroleum coke, natural gas, etc.) used to heat the raw materials used in the cement making process and from the thermal decomposition of those materials in the heating process itself.  Because it is considered a large facility, Lehigh is regul​ated by the State’s Cap and Trade regulation for greenhouse gasses (GHGs).

    To lower its carbon footprint, the facility is investigating the possibility of using biomass as an alternative fuel in the future.  Lehigh is also partnering with a local company to pilot a new technology to capture stack gases to produce a cementitious material.  Lehigh is piloting the carbon capture technology at its Redding plant.  The press release can be viewed at:

    Lehigh stated its commitment to lowering its global carbon footprint.  A Lehigh representative said they have achieved a 22% reduction of net CO2 emissions per metric ton of cementitious material globally as of 2019, compared with 1990 levels.  Their 2030 target of a 30% reduction has recently been brought forward to 2025, with a new CO2 reduction goal of 33% by 2030.

    The Air District does not have the authority to require Lehigh to switch to a different fuel source.  However, Lehigh may be able to switch to a different fuel source provided it receives permit approval from the Air District to ensure all Federal, State and Air District requirements are met.  Currently, Lehigh uses 100% petroleum coke for fuel at the kiln and is allowed to use coal and/or a mixture of coke and coal when coke is not readily available.  In addition, natural gas can also be used for start-ups and supplemental fuel.

    There are several truck emission reduction strategies for diesel particulate ongoing in the State of California.  The California Air Resources Board (CARB) regulates and enforces air regulations for heavy duty diesel vehicles.  In addition, starting January 1, 2020, the Department of Motor Vehicles (DMV) verify a truck’s compliance with CARB’s Truck and Bus regulation prior to issuing a DMV registration.  To assist truck owners/operators comply with state requirements, the Air District has offered grant funding (incentive funding) to help offset costs associated with upgrades to reduce diesel particulate emissions.  CARB has also provided assistance through its truck loan assistance program.

    Unfortunately, Air District staff are unable to answer this question.  We are not sure what the questioner is referring to when he/she states, “that Lehigh is listed in the non-attainment listing”.  We would be happy to revisit this question once the question is clarified.  Lehigh must comply with all federal, state and Air District (air pollution) regulations at all times in order to maintain compliance.  The Air District takes enforcement action when non-compliance is documented.

    Lehigh is required to submit a permit application to the Air District in order to incorporate the new NOx and SO2 requirements of the Consent Decree into its Title V permit.  This will not happen until the United States Environmental Protection Agency (EPA) approves the final SO2 emission limit, which will be determined by the Consent Decree’s SO2 Set and Test Protocol.  Please keep in mind that all federal, state and Air District (BAAQMD) requirements must be met regardless of whether the requirements are listed in the Title V Permit or not.

    Regulation 11, Rule 18 (11-18) is designed to ensure emissions of Toxic Air Contaminants (TACs) from existing facilities, such as Lehigh, do not pose an unacceptable health risk to people living and working nearby.  As with any Air District regulation, Air District staff ensure the facility complies with the applicable 11-18 standards, administrative, monitoring, and record keeping requirements.  Enforcement action is taken for non-compliance.  A copy of the rule can be found on the Air District’s website at

    Currently, the Air District is reviewing the 11-18 Health Risk Assessment (HRA) for the facility, which is an analysis that estimates the potential for increased likelihood of health risk for individuals in the affected population that may be exposed to emissions of one or more toxic air contaminants (TACs) from the facility.  This is one of the initial steps in the 11-18 regulatory process.

    During the pandemic, the Air District has had inspection staff available to answer and respond to Lehigh air pollution complaints and to conduct facility inspections when necessary.  As with most oversight agencies, the Air District had to adapt to the realities of the pandemic and take measures to keep its inspection staff safe but that did not hinder it in its ability to oversee compliance at Lehigh.

    Particulate matter (PM) is a serious health concern that can increase the risk of developing cardiovascular disease, asthma, and cause eye and throat irritation.  In addition, PM containing toxic air contaminants (TACs) can increase the risk of cancer and have other serious health effects.  To regulate and reduce PM emissions at Lehigh, the Air District adopted regulatory rules and set permitting requirements at its disposal.  For example, fugitive dust mitigation measures are required by the Air District’s Portland Cement Manufacturing Regulation 9, Rule 13, as well as by the facility’s District approved Fugitive Dust Control Plan.  Process equipment must be abated and monitored.  Opacity requirements must be met throughout the facility.  To ensure these and other required particulate matter mitigation measures are in compliance, the Air District maintains a strong field presence by regularly inspecting activities at the facility.

    The public may report an air quality complaint to the Air District’s 24-hour complaint line at (800) 334 ODOR (6367) or online at

    The Air District responds to every air pollution complaint with a field response investigation.  All air pollution complaints are received via a 24-hour complaint line at (800) 334-ODOR (6367) or online at

    Air pollution complaints are generally handled by the Air District in the following manner.  The complaint will be dispatched to an inspector who will contact the complainant to discuss the complaint and make arrangements to meet with the complainant, if available.  The inspector conducts his initial investigation in and around the complainants or nearby area to determine if the concern is still impacting the complainant and or other residents or workers.  Ideally, the complainant and inspector meet.  If the complainant’s concern is observed by the inspector, it is tracked to its source, if possible, which may or may not be the alleged source.  The inspector conducts an investigation at the alleged source or inspector determined source and takes enforcement action if air quality violations are found.  The inspector works with the facility/source to resolve the air quality concern, whenever possible.  After the investigation is complete, the inspector follows-up with the complainant and provides the results of the complaint investigation.  A report is made for documentation.  A complainant is welcome to request a copy of the report from the inspector, which will be sent to him/her after it is completed and processed.

    City of Cupertino

      Maximum truck size and weight is set by the CA vehicle code. The County and/or the City do not have the authority to change these standards.

      Speed limits are set with objective engineering standards and are not arbitrary.

      With special high fines for violation? 

      Similarly, the City does not set fines for moving violations.

      Can we restrict times they can use the roads?

      No, public roads cannot have hour restrictions.

      The Historic De Anza Trail Project in Cupertino is currently on hold. Union Pacific Railroad is not interested in allowing any trail amenity within their right of way.

      San Francisco Bay Regional Water Quality Control Board

        Not that I know of. Lehigh does not operate a dam or withdraw water from Permanente Creek. It does have a permit to discharge water to Permanente Creek under specific conditions (typically during or following wet weather).

        It hasn't rained much. With respect to precipitation, the San Francisco Bay region has one of the world's most variable climates, and we're currently experiencing moderate-to-severe drought conditions.

        My agency, the Regional Water Quality Control Board, does not oversee water rights. The State Water Resources Control Board does. My understanding is that Lehigh does not intentionally withdraw water from Permanente Creek to use onsite; therefore, it does not require any specific water rights.

        Santa Clara County, Planning and Development Department

          The Reclamation Plan Amendment (“RPA”) application submitted by Lehigh states that the new pit mining area will be in use for approximately 15-30 years and will be reclaimed concurrent with mining activities.

          Quarries must be reclaimed such that slopes are stable, water quality is protected, and vegetation is reestablished.  How specifically these are accomplished is determined by a reclamation plan that all quarries must operate under and which is usually approved by the jurisdiction where the quarry is located.

          Some reclamation plans may include an expiration date that specifies the end date.  Otherwise, quarries typically remain in operation as long as there is material available.

          Lehigh’s property is primarily designated as Hillsides and Agriculture, with some parcels designated as Agriculture under the County’s General Plan.  These designations allow for very low-density residential development (20-160 acres per dwelling unit).  Currently, there are no proposals to change these underlying land use designations to residential.

          The 2012 Reclamation Plan Amendment (RPA) states that the site, including Permanente Creek, will be reclaimed by 2030.  The 2019 RPA application states that Permanente Creek restoration will be completed during reclamation phase 1, and states that phase 1 will be completed in approximately 20 years. 

          Lehigh has submitted a grading permit application for the Permanente Creek restoration work, and preparation of the required Environmental Impact Report (“EIR”) began in March 2021. Once the EIR has been completed, circulated for public comment, and certified by the County, the County may issue a grading permit to Lehigh for the Permanente Creek restoration work, after which Lehigh could begin restoration.

          No. Both recent Notices of Violation issued by the County (Haul Road NOV and Sediment Discharge NOV) have been abated.

          The 1972 Ridgeline Protection Easement was granted to the County by Lehigh. Lehigh has requested that the Board of Supervisors modify the Ridgeline Easement, which the Board of Supervisors may or may not approve.

          The approved 2012 Reclamation Plan Amendment specified that onsite material from the West Material Storage Area will be used to backfill the main pit. The 2019 RPA application specifies that Lehigh will import and use clean fill to backfill the main quarry pit. The environmental impacts resulting from the 2019 RPA application will be evaluated through the California Environmental Quality Act process and considered by the Santa Clara County Board of Supervisors. As the decision maker, the Santa Clara County Board of Supervisors will have to consider the impacts resulting from the importation and use of clean fill, and make certain CEQA findings in order to approve or deny the use of imported fill.

          Truck trips in this area may be coming from a variety of different sources. The EIR for the 2019 Reclamation Plan Amendment application will evaluate the increase in traffic associated with Lehigh’s proposed importation of clean fill and propose mitigation as necessary.

          Lehigh has not proposed to use rail.

          There is no specified haul route or time restriction. The cement plant operates under a Use Permit granted in 1939 and the conditions of approval associated with that Use Permit do not impose any time restrictions or specify any haul routes.

          Under Lehigh’s 2019 Reclamation Plan Amendment (RPA) application, additional mining of the main quarry highwall will occur concurrent with placement of imported fill in areas where no conflict with access to reserves occurs, within the first 20 years after RPA implementation. The process will be completed after mining in the main pit has ceased, approximately 30 years after plan implementation.

          This phasing, and the reclamation plan proposed in the 2019 RPA application will be evaluated by the project EIR and must be approved by the Santa Clara County Board of Supervisors in order to be implemented.

          Under the approved 2012 Reclamation Plan Amendment (RPA), the quarry will be fully reclaimed by 2030.  Under the 2019 RPA application, it is estimated that the quarry will be fully reclaimed approximately 30 – 40 after plan approval.

          Santa Clara County, Office of the County Counsel

            Civil proceedings may be filed in court by members of the public, with standing, objecting to the Lehigh mining expansion. 

            If the Quarry is abandoned, the County may take over the Quarry to complete reclamation using the financial assurances posted to fulfill the reclamation.  The Board of Supervisors may determine future land uses that are allowed on the Quarry site.

            Under the current circumstances, the County is not aware of any authority that would enable it, or any other public agency, to permanently shut Lehigh down and restore the disturbed area.

            US Environmental Protection Agency

              The California Emissions Inventory Data Analysis and Reporting System (CEIDARS)is a database management system developed to track statewide criteria pollutant and air toxic emissions. You can access this data and search rankings of facilities at the following website:

              The lime injection system is actually a separate process not related to the limestone.  Further engineering would need to be conducted to know the impact of the lime injection system on mercury control. The consent decree does requires Lehigh to submit a protocol to EPA for approval “that describes how the Lime Injection System for the Cupertino Kiln will be designed, installed or modified, configured, and tested to determine the configuration and operation resulting in the minimization of emissions of SO2 to the greatest extent practicable without violating any local, state and/or federal limits for other pollutants.”

              As BAAQMD has addressed in its FAQs, the consent decree includes provisions to address the potential development of a detached plume resulting from operation of NOx emissions control equipment.

              Valley Water

                Permanente Creek consists of approximately 13 miles of channel draining an estimated watershed area of over 17 square miles. Permanente Creek does not receive supply from a Valley Water reservoir or pipeline turnout to supplement flow throughout the year. Creek flow is dependent upon rainfall and runoff generated from the surrounding watershed area. As a result, there is often no surface flow during the dry season. In wetter years, there may be times when flow is observed in the creek for extended periods due to high groundwater levels. This baseflow results from shallow groundwater seeping into the creek.

                We recommend contacting the State Water Resources Control Board (SWRCB) for more information on Lehigh’s water rights. Lands abutting a creek may enjoy riparian rights, which allow diversions of the natural flow of water for reasonable use required for those lands. California Water Code §5101 requires each person or organization that uses diverted surface water or pumped groundwater to file with the SWRCB a Statement of Water Diversion and Use prior to July 1 of the following year.

                We were not able to find any evidence of an appropriative right for Lehigh Cement Company (or Hanson) in Santa Clara County from a cursory search of the e-WRIMS Water Rights database:

                Unlike the more permeable, interconnected aquifer sediments beneath the valley floor, groundwater beneath Lehigh occurs in bedrock. Water from Permanente Creek, including runoff and water discharged from Lehigh, flows down to Permanente Creek and ultimately the San Francisco Bay.  Permanente Creek is listed on the State’s list of impaired water bodies for selenium water quality objective exceedances. From the Water Board’s website: The 13-mile long creek was listed as impaired for selenium because observed total selenium concentrations in the water column exceeded the applicable chronic water quality objective of 5.0 micrograms per liter (µg/L).

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