The U.S. Environmental Protection Agency has filed a complaint against Mauna Loa Macadamia Nut Corp. on the Big Island for failing to close three large-capacity cesspools by an April 2005 deadline. It is proposing a penalty of up to $157,500.

The federal agency announced the action yesterday, saying such closures are needed to protect Hawai'i's water resources. Alexis Strauss, director of the EPA's water division for the Pacific Southwest region, added: "While we continue to pursue violators, it is unfortunate that companies such as Mauna Loa require this level of oversight to fully comply with EPA's regulations."

Mauna Loa, a subsidiary of the Hershey Co., owns and operates a macadamia nut processing plant and a visitor center. No one from Hershey could be reached immediately to comment on the complaint and recommendation.

The EPA said that in July 2004, it notified the company of the April 2005 deadline to close its large-capacity cesspools. Such cesspools discharge raw sewage into the ground, which results in disease-causing pathogens and other contaminants — polluting groundwater, streams and the ocean, the EPA said.

The agency said one of its contractors inspected the Mauna Loa facility in October 2005 and was told closure plans were being developed. A subsequent inspection in August 2006 found the three large-capacity cesspools were still in use, the EPA said.

In August 2007, the company completed work to close and replace its large-capacity cesspools with an approved wastewater system. Mauna Loa's wastewater facility has the capacity to serve about 700 people per day.

The EPA's complaint proposes a penalty of up to $157,500 based on the company's violations and any financial gains Mauna Loa obtained from not closing the cesspools by the April deadline.

The case was originally referred to the EPA by the state Department of Health's Wastewater Branch.

A large-capacity cesspool discharges untreated sewage from multiple dwellings, or a nonresidential location that serves 20 or more people per day. The regulations, which prohibit large-capacity cesspools as of April 2005, do not apply to single-family homes connected to their own individual cesspools.

Historically, cesspools were used more widely in Hawai'i than in any other state.

Reach Robbie Dingeman at rdingeman@honoluluadvertiser.com.