Mayor Mufi Hannemann's administration has filed a Freedom of Information Act lawsuit against the U.S. Environmental Protection Agency, demanding access to records that justify EPA's refusal to waive federal clean water standards for the city's two largest sewage treatment plants.

The suit was filed by City Corporation Counsel Carrie Okinaga and a Los Angeles law firm, Bingham McCutcheon, hired to represent Honolulu in a long-running dispute with the EPA over the necessary level of treatment for effluent discharged through ocean "outfalls" offshore of the Sand Island and Honouliuli wastewater plants.

Last year, the EPA refused to renew earlier waivers of treatment standards granted the two facilities, requiring that both be upgraded to meet full secondary treatment standards required of wastewater plants elsewhere in the country.

The city argues that the upgrades are both environmentally unnecessary and prohibitively expensive when combined with the cost of numerous other largescale sewer infrastructure improvements now under way. One estimate of the price tag for the upgrades is $1.2 billion.

The new lawsuit said release of the EPA records "is in the public interest" because disclosure would "significantly contribute" to understanding the EPA's reasons for not renewing the plant waivers.

The city submitted Freedom of Information Act requests for the records in April and December of last year, but the EPA has withheld or heavily blacked out numerous records, citing attorney confidentiality or other exemptions contained in the public records law, the suit said.

The majority of the records produced under one FOIA request "were entirely redacted with the exception of the to, from, date and/or subject lines," the suit said.

"Such redactions render the released documents entirely devoid of content," the city argued.