Anaconda’s soil is so disturbed from 97 years of smelting that there is disagreement between the Environmental Protection Agency and the Opportunity and Crackerville residents as to how much arsenic would have been in the soil prior to the smelting years. The EPA estimates the level at about 25 parts per million of arsenic, while Opportunity and Crackerville litigants claim it was closer to 8 ppm.

EPA has not attempted to reduce the arsenic in the soil even to its own background estimate — rather, it has set a limit of 250 parts per million.

That threshold was “expected to reduce the level of overall risk to human health close to a level EPA deemed tolerable,” according to an Opportunity and Crackerville legal document.

In addition to the soil claim, Opportunity and Crackerville homeowners want a trench built underground to stop a plume of contamination from reaching their drinking water wells. The EPA says a drain already in place prevents that from happening.

Atlantic Richfield said in its court filing it has spent $470 million in clean-up costs on the Anaconda Superfund site. That includes both Opportunity to the east of Anaconda and Crackerville to the southeast.