Revised On: Jan. 23, 2024 - 2:30 p.m.

Location: Sierra Mining and Crushing Company LLC (composting area of manufactured product), 8665 S. Alvernon Way, Tucson, Arizona 85756

Discovery Date: December 2010

Contaminants of Concern (COCs): Emissions resulting from smoldering compost pile

Affected Media

• Soil
• Air
  
  

What are my health risks?

For Soil | There is little to no health risk unless there is contact with skin or ingestion of contaminated soil.

Site Summary

This facility practices the crushing, mining, shredding and sifting of received gravel, asphalt, wood and green waste which are processed over time.  Resulting products consist of a variety of landscape materials including gravel, crushed concrete, topsoil, ornamental rock, solid amendments, fuel for biomass power plants and horse bedding. In June 2010, a fire occurred at a 3.62-acre compost pile consisting of wood and green waste located on the southeast portion of the property. To address the fire, the entire burn pile was covered with dirt and topsoil. To date, the covered wood and green waste continues to smolder and has occasional flare-ups from venting areas and subsurface pressure. The site continues to reduce the pile, remove and recycle usable materials, and manage flare-ups.

Corrective Actions

• Complaint response inspection completed in November 8, 2010 in response to the fire.
• Consent order signed March 25, 2014, containing an approved plan to remove and dispose of materials to minimize fire flare ups and remediate entire compost pile.
• Consent Judgment filed Dec. 14, 2021, establishing volume of material removed and reporting required monthly.
• Conducting monitoring of the soil-covered pile of vegetative and wood waste and nuisances to assess temperature and evidence of potential fire areas.
• Submitting monthly status and monitoring reports on quantities of waste removed and disposed from pile and separated waste for recycling.
• Documenting episodes of fires and flare-up occurrences and management activities of the active pile.