Hawaii County firefighters worked Wednesday evening to assess whether a threat was posed to area residents in Kapoho after the Puna Geothermal Venture plant went offline and vented steam for 15 to 20 minutes.
Two fire department crews with air monitors canvassed Pohoiki Road and Leilani Estates at about 5:15 p.m., to monitor air quality. A fire department spokesman said that all results weren’t in, but that readings taken at the entrance to PGV had so far found no hydrogen sulfide, a potentially deadly byproduct of the geothermal process.
Later in the evening, PGV plant manager Mike Kaleikini reported that during the event, a peak reading of 19 parts per billion of hydrogen sulfide was measured at the plant. He noted that was far below the permitted hourly limit of 25 parts per billion.
“The plant tripped offline, a little bit before 4 p.m., and we do not know exactly why at this point,” he said. “We’re still investigating.”
He added that all wells were shut within about 20 minutes of the power outage, but that during that time, steam was released from the plant’s emergency steam release system.
The last time the plant experienced an unscheduled venting of geothermal steam was in November 2011, Kaleikini said.
“While there is no danger to the public, some residents have reported the presence of hydrogen sulfide odor,” according to an alert issued by Hawaii County Civil Defense at 5:12 p.m. “The Department of Parks and Recreation has opened the Pahoa Community Center for residents who prefer to remain outside the area.”
Area resident Jeana Jones said she was driving on Pohoiki Road when she saw the steam plume, which she described as “screaming loud.” She said she knew immediately that it was coming from PGV.
“I was absolutely concerned,” she said.
Jones said that she could smell a faint odor of hydrogen sulfide.
Last summer, Hawaii County’s Planning Department received a record 25 applications from homeowners living near the plant looking to sell their homes to the county and relocate as part of a program aimed at helping families concerned about health and other impacts from the plant.
Five relocations have been approved to date, with the most recent being in 2012.