Rock quarries create invisible dust particles proven to cause silicosis—a progressive, incurable lung disease. Long-term exposure to particulate matter is strongly associated with heart disease, stroke, infertility, and pregnancy complications.
Proven Health Hazard
Dust created by gravel quarries is considered respirable crystalline silica, a type of particulate matter. Studies have established a strong link between these particles and the following health effects:
Over 12,000 residents within five miles of the proposed quarry will be affected by cascading injurious events resulting from particulate matter carried by prevailing winds. Young children, the elderly, and those with respiratory illnesses such as COPD, emphysema, asthma, and progressive lung disease will be most impacted.
The San Antonio-New Braunfels metro area has pediatric asthma rates of 1 in 7 (nearly twice the national average) and Comal ISD already has over 2000 students with an asthma health alert on file. Particles produced by rock-crushing operations will increase air pollution and exacerbate this health risk for Comal ISD students.


- Health Risks Associated with Exposure to Airborne Pollutants Arising From Quarrying and Aggregate Processing
- Airborne Particulate Matter (PM) Exposure and Health Risks Associated with APOs in Texas
- Air Quality and the Limestone Aggregate Industry in Comal County, Texas: A Call for Policy Change
- Evidence that Comal County Residents May Be at Risk for Exposure to Air Pollution from the Aggregate Industry
Invisible Toxins
You can’t even see it—but you’re certainly breathing it. Respirable crystalline silica is categorized and monitored as PM 2.5 (fine particulate matter 2.5 micrometers or smaller—less than 1/20 the width of a human hair) and PM 10 (10 micrometers or smaller). Both sizes are inhaled and can go directly to lungs and bloodstream.
Quarry blasting, crushing, and hauling operations emit high levels of carcinogenic particulate matter. Visible dust (larger particles) is also created by movement of front-end loaders, mining trucks, transfer conveyors, excavators, bulldozers, and utility vehicles.
Over 80 formal complaints have been filed against Vulcan in Texas alone. And over 35 violations occurred at a single Vulcan Materials plant (Loop 1604 in San Antonio).
Violations at Vulcan Plant in San Antonio
With Vulcan’s samples they found silica and manganese inside my home, and that’s unlike a typical household profile. Outside they found fly ash, which is very toxic. There are permit violations dating back all the way to 1991.
Noxious Gas & Air Pollution
Daily emissions of diesel exhaust from plant equipment and hundreds of gravel trucks generate nitrogen oxide, sulfur dioxide, carbon monoxide, and volatile organic compounds (VOCs).
Additionally, when these pollutants combine with sunlight, they create ozone. The San Antonio region’s air quality continues to worsen with higher and higher ozone levels exceeding the nation’s health-based standards. With these ozone violations predicted to mark us with a “non-attainment” status, by August 2018 we should expect the EPA to issue their ozone designation decision for eight counties in the San Antonio-New Braunfels Area.
The proposed quarry and the additional truck traffic would significantly impact regional air quality, even beyond a five-mile radius of the quarry site.


Air Pollution News & Updates
Citizen Groups File Motion Against Comal Vulcan Quarry Air Permit
December 19, 2019
Stop 3009 Vulcan Quarry and Friends of Dry Comal Creek filed a motion for rehearing their case opposing permit requested by Vulcan Materials.
In Latest Development, SOAH Disagrees with Citizen Groups on Proposed Vulcan Quarry
September 3, 2019
SOAH recommends TCEQ issue draft air quality permit to Vulcan Construction Materials for Comal quarry. Citizen groups prepare for next steps.
What We Have Learned About the Air We Breathe
August 4, 2019
Local scientists perform sampling of air quality, contaminant pollution levels, uncover pollution far above EPA safety thresholds in Comal County, Texas.
Trial Portion of Hearing on Proposed Comal Quarry Concludes
June 13, 2019
The hearing on the merits against Vulcan Construction Materials has ended. SOAH judge plans to render decision in case by September 3, 2019.