The state Department of Health fined Hu Honua Bioenergy, a renewable energy firm, $25,000 for illegally discharging wastewater last month at its Pepeekeo facility on Hawaii island.

The DOH Clean Water Branch cited the firm for discharging the industrial wastewater on Nov. 9 without a permit or state authorization.

“Our inspectors have confirmed a worker for Hu Honua Bioenergy opened a valve on its industrial wastewater treatment tank and allowed the contents of the tank to discharge from their facility into the environment,” said Keith Kawaoka, deputy director of the DOH Environmental Health Administration, in a news release. “This is a serious violation as discharges without permit authorization are strictly prohibited to protect human and environmental health from exposure to pollutants, which can cause serious and sometimes irreparable harm.”

A state investigation found that between 3,500 and 32,500 gallons of treated industrial wastewater that included freshwater, acidic metal cleaning solution and residue from the descaling of a boiler was generated between Nov. 2 to Nov. 6. The wastewater, which contained high levels of iron, had been filtered and neutralized before being illegally discharged.

Besides the penalty, the state is requiring Hu Honua Bioenergy to train its employees within 30 days on environmental regulations and establish standard operating procedures to prevent future discharges. The company, which couldn’t immediately be reached for comment, may request a hearing to contest the violations within 20 days.