The Puna geothermal plant on the Big Island has been fined $23,700 by the state Department of Health for violations of the Clean Air Act that include uncontrolled releases of hydrogen sulfide during Tropical Storm Iselle.

The storm hit the islands on August 7, knocking out power in the area and damaging utility transmission lines. The 38-megawatt plant, owned by Puna Geothermal Venture, was shut down and steam was released to relieve pressure. A faulty pressure release valve caused 39 pounds of hydrogen sulfide to be released into the air over the course of about two hours without first passing through an abatement system, according to a notice of violation issued by the health department on Thursday.

Puna geothermal

Puna Geothermal plant

Courtesy of Puna Geothermal Venture

Hawaii Civil Defense alerted area residents to evacuate their homes if they felt ill. The gas emits a rotten egg smell and can cause sore throat, eye and respiratory irritation, nausea and vomiting, Barbara Boxer, the state toxicologist told Civil Beat. In very high concentrations it can be lethal.

The state health department doesn’t know what the concentration levels were after the release because the plant’s air monitoring equipment was down for a week due to the loss of electricity, said Boxer. Readings taken by PGV around the plant with a hand-held device registered low concentrations of hydrogen sulfide, but Boxer noted that the gas could have been blown out into the community at higher concentrations.

The state health department found that the hydrogen sulfide emissions exceeded clean air standards. Puna Geothermal Venture was also nine days late in filing an emissions report.

Puna Geothermal Venture could have been fined as much as $25,000 a day for the violations, but the fines were reduced during the negotiation process after issues such as cooperation and the company’s size were taken into account, said Jill Stensrud of the health department’s Clean Air Branch.

Puna Geothermal Venture has 20 days to contest the fines.


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