page_title: California Gulch
section_title: Superfund site
hierarchical_section_title: California Gulch / Superfund site
caption_attribution_description: English: The mining, milling and smelting process that transforms ores into precious metals creates many types of wastes, which contaminated land and waters in and around Leadville.
context_page_description: The California Gulch site consists of approximately 18 square miles in Lake County, Colorado. The area includes the city of Leadville, parts of the Leadville Historic Mining District and a section of the Arkansas River from the confluence of California Gulch downstream to the confluence of Two-Bit Gulch. The site was listed as a Superfund site in 1983.
context_section_description: California Gulch is one of the many Superfund sites in Colorado. The Superfund program is responsible for cleaning up contaminated land and responding to environmental emergencies, oil spills and natural disasters in the United States. California Gulch was placed on the National Priorities List (NPL) in 1983 due to health risks associated with people ingesting and touching contaminants from the former mining operations found in soil, sediment, surface water, groundwater, liquid waste, solid waste, and sludge. A preliminary estimate in 2006 for the damages to aquatic and terrestrial environments was between $53 million and $68 million. The second largest settlement in Colorado history was reached in 2008 when the parties agreed on a $20.5 million natural resource damages settlement.
  Since the 1850s byproduct materials, such as tailings and slag, were left by mining operations. High levels of heavy metals and mine drainage raised concern of high blood lead levels in residents, particularly in children. This hazardous waste and low-pH water also reduced biological diversity and caused stress in the ecosystem, decreasing the trout populations. The most concerning contaminants are arsenic, cadmium, copper, lead, manganese, and zinc.
  Since 1995, removal and remedial activities have been conducted through federal, state, and PRP actions to consolidate, contain and control more than 350,000 cubic yards of contaminated soils, sediments and mine-processing wastes. Potentially Responsible Parties (PRPs) and the EPA work on the cleanup by conducting drainage controls to prevent acid mine runoff, cleanup of residential properties, reuse of slag, and consolidation and containment of contaminated soils, sediments, and mine-processing wastes. The Yak Treatment Plant was also built and it is still in operation. The EPA divided the site into 12 Operable Units (OUs), with the twelfth OU surrounding the whole NPL site and tests the groundwater conditions. The residential areas of Leadville and Lake County are in OU9. The EPA found concentrations of lead in the soil in some areas that exceeded the soil action levels of 3,500 parts per million, causing risk of lead poisoning in the population.
  EPA completed various Five-Year Reviews with the purpose of evaluating the implementation and performance of the Environmental remedy to determine if it is or will be protective of human health (public health) and the environment. The last one was published in February 2017. Current actions for long-term protection include assessment of institutional controls for OUs 1, 2, 4 and 10 to guarantee the continue safety levels, implementation of institutional controls for OU-5, possible investigations in OU-3, and updates and implementation of operation and maintenance plans for OUs 5 and 7.
  The EPA has deleted 9 OUs and proposed to delete several other OUs from the NPL. The EPA and the Colorado Department of Public Health and Environment proposed to delete OUs 4, 5 and 7 from the NPL in August 2014.
  Despite the risk of exposure being low, Pregnant and nursing women, and young children are encouraged to test their blood-lead levels. Lake County continues to offer free blood-lead testing.
caption: The mining, milling and smelting process that transforms ores into precious metals creates many types of wastes, whichcontaminated llandand waters in and around Leadville.
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