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Panel to consider geothermal health study: 67 pounds of hydrogen sulfide released Aug. 7 during venting at PGV

PGV’S Aug. 7 steam release

• Hydrogen sulfide released: 67 pounds.

• Amount detected with hand-held monitors (in parts per billion): 25 ppb (8:15 p.m. on Pohoiki Road), 24 ppb (8:03 p.m. on South Leilani Avenue), 10 ppb (7:55 p.m. on West Hinalo Street), 12 ppb (7:50 p.m. on East Hinalo Street).

• Puna Geothermal Venture’s permit threshold: 25 ppb hourly average.

*PGV maintains three monitors on its fenceline. The state Department of Health operates one in Leilani Estates. None were operating during the incident after losing power.

The Windward Planning Commission will consider approving a $750,000 study Thursday to determine if geothermal development in Puna has harmed the health of residents.

The proposal will be on the table almost a month after Puna Geothermal Venture released an estimated 67 pounds of hydrogen sulfide after winds from Tropical Storm Iselle knocked out its transmission lines. The 38-megawatt plant shutdown as a result, causing it to release steam to relieve pressure.

About 10 times more hydrogen sulfide was vented during that release than a similar incident that occurred in March 2013, according to the state Department of Health.

The study, which would take up to three years to complete, was one of the main recommendations of a Hawaii County-funded geothermal working group. The study would be funded by the county’s geothermal asset fund.

The Aug. 7 release renewed geothermal fears and occurred as the storm was hitting the area, preventing nearby residents from leaving their homes.

Members of the Puna Pono Alliance, a group that has been critical of geothermal development, have said they’ve heard from dozens of people who experienced symptoms during the incident that could be related to hydrogen sulfide exposure, including scratchy throats, rashes, fatigue and headaches. Several also said they fell unconscious during or following the release, according to the group.

The group is documenting those reports in written and video testimony. A PGV spokesman said employees working during the release have not reported health effects.

Gas monitors were disconnected from the power grid because of the storm and were offline when the release occurred. Civil Defense Administrator Darryl Oliveira said generators have been provided to PGV to prevent that from happening again.

A PGV employee used a hand-held monitor during the incident to take several readings downwind from the plant. The highest reading was 25 parts per billion of hydrogen sulfide on Pohoiki Road.

That’s below hazard levels, but geothermal critics think the readings might not paint the whole picture since they were not taken continuously during the 150-minute release. The readings, taken during 25 minutes, also are insufficient to determine if PGV violated its air permit since that threshold is based on an hourly average, acknowledged DOH clean air branch manager Nolan Hirai.

A violation would occur if readings averaged 25 ppb or higher during an hour.

The average reading taken during the 25-minute period was 16.2 ppb, according to a report from Cardno Tec Inc.

It’s also difficult to determine whether the reported symptoms could have been caused by hydrogen sulfide based solely on how much was released, Hirai said.

Other factors play into exposure levels, including wind speeds.

“The high wind speeds of Iselle probably caused greater dispersion resulting in a wider spread of H2S emissions but at lower concentrations,” Hirai said in an email. “PGV conducted hand-held monitoring during the August 7th release and had readings around 25 ppb and below. At this level, health impacts are not expected.”

Gary Gill, deputy environmental health director, also made a similar statement to the Tribune-Herald last month.

“Obviously, we are concerned about any potential health impacts this incident may have caused,” Hirai said Tuesday.

He said DOH’s hazard evaluation and emergency response office is handling the health complaints.

PPA members have said that wind speeds remained fairly low at the ground level and might not have dispersed the gas as much as health officials think.

While DOH might not be able to assess the hazard level from the incident, Hirai said it continues to investigate to see if other violations occurred pertaining to notification, record keeping and other procedural requirements.

Oliveira said the county provided two hand-held monitors to nearby residents of PGV following the incident. Civil Defense also still plans to add two stationary monitors near the plant, he said.

Email Tom Callis at


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