10/23/08 Terrebonne
A report by the Oregon Department of Human Services State Public Health Division found that soil and groundwater at a former Central Oregon surface mine pose no apparent health hazard under current, industrial land-use conditions. The health division believes that dust blowing from the site is unlikely to cause serious illness but more data is needed to rule out the possibility.
The report, released Thursday by the health division's Environmental Health Assessment Program (EHAP), evaluated the potential health risks associated with living near the Lower Bridge Mine in Terrebonne, Ore. As part of the evaluation, EHAP reviewed air, water and soil data and met with nearby residents to hear their concerns.
EHAP also found that dilapidated buildings, piles of scrap metal and scrap wood pose a physical health hazard to trespassers, particularly because they are known to frequent the site.
The 550-acre site is a former surface mine where diatomaceous earth (DE) was mined and processed from 1930 to 1958. DE is useful in a variety of commonly used products, including as a mild abrasive in toothpaste and metal polishes. DE is comprised of microscopic skeletons of fossilized single-celled aquatic organisms, which are found in large deposits throughout Oregon, Washington, Nevada, and California.
Among the report's conclusions are:
- Soil and groundwater from the mine currently pose no apparent public health hazard to nearby residents under current land use conditions. This is because none of the contaminants measured in areas where hazardous waste was stored or where polychlorinated biphenyl (PCB) contamination occurred exceed comparison values set by the Agency for Toxic Substances and Disease Registry. Radiological surveys found no readings above local background level.
- Dilapidated buildings and piles of scrap metal and loose wood pose a public health hazard (physical hazard) to trespassers. While "No Trespassing" signs are posted around the perimeter and barriers block access to motorized vehicles onto the site, limited physical barriers are in place to restrict pedestrian access. People could access these dangerous areas and become injured.
- EHAP does not expect inhaled dust from Lower Bridge Mine to cause silicosis or lung cancer because the concentration of crystalline silica in the air is likely too low to cause these health effects in nearby residents. However, because existing data are insufficient, EHAP is unable to conclude whether inhalation of dust from the mine could cause silicosis or lung cancer (indeterminate public health hazard).
- EHAP is unable to determine whether other long-term health effects of airborne dust from the site and other sources are likely (indeterminate health hazard). This is because data about the size and concentration of dust particles in the air that residents breathe is insufficient.
The report recommends, among other things, that owners of the site continue to suppress the dust, sample the soil and air for potentially harmful crystalline silica, and remove scrap and old buildings.
The Deschutes County Planning Commission is considering a request to change the site's zoning from industrial to residential. If the rezoning occurs, EHAP recommends further evaluation prior to building any proposed development.
A meeting to discuss the report with local residents will be held Monday Nov. 3, 2008 from 6 p.m. to 8 p.m. at the Redmond Senior Center, 325 NW Dogwood Ave., in Redmond.
See the full report on the Web at www.healthoregon.org/ehap/
