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Testing shows soil safe in Marshall Fire burn areas

Areas affected by the Marshall fire show the levels of metals and asbestos in the soil do not pose a significant health risk
Colton Trailhead2
Colton Trailhead on Dec. 31, 2021


Results from testing conducted by Boulder County Public Health (BCPH) in areas affected by the Marshall fire show the levels of metals and asbestos in the soil do not pose a significant health risk and are, in most cases, consistent with surrounding areas that were not impacted by the fire.

BCPH selected 26 test sites. Twenty locations were chosen because a home or structure was completely destroyed. Six locations were selected outside the burn areas to set a baseline for the amount of metals normally found in soils in the region.

Each location was tested for 17 metals and asbestos at depths of 0-3, 3-6, 6-9 and 9-12 inches. A small number of tests showed slightly elevated levels of arsenic that are considered safe and within the range of normal levels for the area. No asbestos was detected at any of the testing locations.

Two of the tested properties returned results that were above normal levels, but BCPH does not believe the Marshall fire caused the elevated levels.

Tests from one property in Old Town Superior showed elevated antimony, arsenic, and cadmium levels. To ensure the elevated readings were isolated to one property and most likely unrelated to the Marshall fire, BCPH conducted additional soil testing at surrounding properties and found no additional high levels.

BCPH selected each test site to provide a wide variety of properties and environmental conditions. Criteria for selection included the soil types, age of affected homes, extent of the destruction, number of people nearby and proximity to other testing locations.

The results will help BCPH create testing recommendations for people whose homes and properties were affected and the development of removal and cleanup guidance.

BCPH also recommends that testing requirements for private debris removal permits be modified to provide safeguards for public health while reducing the financial burden on homeowners.

For more information on the Marshall fire, visit

For answers to common questions about air, water and soil quality, visit

For questions about air quality, email [email protected]