The U.S. Environmental Protection Agency and state Health Department have completed removal of toxic soil at a Kilauea neighborhood on Kauai, the agencies announced Monday.

Crews removed more than 814 tons of contaminated soil from a site once used as a pesticide mixing and storage area at the Kilauea Sugar Mill, which shut down in 1971 after 94 years in operation.

The site was less than a half-acre at two residential properties and behind a commercial warehouse. Each building had been constructed at the former pesticide mixing site on Aalona Street near the intersection with Oka Street.

Cost for the cleanup was estimated at $700,000.

The Health Department’s Hazard Evaluation and Emergency Response Office’s Site Discovery Program sought assistance from the federal agency’s Superfund Emergency Response and Removal Program. The cleanup took place at the end of July, continuing into mid-September.

The department began an investigation in 2010 after historical documents were found suggesting there was toxic surface soil containing arsenic and dioxin from pesticides used at the mill. Soil tests indicated high levels of contaminants in a drainage ditch area behind the warehouse.

Tests of other properties near the warehouse and two residential properties showed no signs of significant contamination, according to a July report in the Hawaii Journal of Medicine & Public Health by Fenix Grange, supervisor of the hazard evaluation office, and other health officials.

Exposure to high levels of arsenic can cause long-term health problems and increase the risk of cancer, according to the report. Symptoms of exposure include stomach pain, vomiting, diarrhea and "pins and needles" sensations in hands and feet. Short-term exposure to high levels of dioxin may result in skin lesions such as chloracne, patchy darkening of the skin and damage to the heart and liver. Long-term exposure can affect the immune, nervous and reproductive systems, according to the EPA.

Health officials held community meetings to discuss the soil contamination. Toxicologists from the Rocky Mountain Poison and Drug Center also met with area physicians.

According to the report, the department has found no evidence of exposure in people residing on or near the former pesticide mixing area.

"Many of the symptoms of arsenic exposure, however, have other causes as well and would be extremely hard to associate with past pesticide exposures in the small rural populations living in Hawaii," the report said.

Crews permanently capped the ditch with a concrete culvert barrier and removed the top two feet of soil in the front and backyards of the two residential properties, replacing it with new, clean soil.

Grange said in an interview the homes on the properties are completely safe for residents.

"There will be long-term controls on all properties so it remains protected in the future," she added.