By Associated Press
Dauphin Island AL – Problems at a natural gas platform near Dauphin Island may have been responsible for a cloud of toxic gas that swept across the island's east end and sickened dozens of people, an ExxonMobil official said Tuesday.
Dauphin Island Sea Lab classrooms were evacuated, and a half dozen people visited the town's doctor apparently after exposure to hydrogen sulfide, a poisonous and foul-smelling gas that occurs naturally underground with highly sought methane.
ExxonMobil officials told the Press-Register in a Wednesday story that the noxious gas may have been released during a brief incident at the company's Mobile Bay 76 facility, the double-platform that serves as the hub of the company's Alabama gas harvesting operations.
The company's problems began with dropping pressure in a line from the mainland that provides clean, processed natural gas to the platform, said Paul Dieffenthaller, chief of ExxonMobil's operations in Mobile Bay.
He said operators later discovered there was trash in the fuel gas line. The line is used to feed an ever-burning flare in the emergency vent high above the western end of the platform as well as the platform's power generators, Dieffenthaller said.
The pressure continued to drop, and that may have extinguished the flare, he said.
Ordinarily, when operations shut down and the entire system "de-pressurizes," any deadly hydrogen sulfide in the gas escaping through the vent is burned, or "flared," and converted to sulfur dioxide, another toxic gas more quickly dispersed by the nearly constant sea breeze.
But on Tuesday, the flare was out for approximately eight minutes, and the gas escaped into the atmosphere unadulterated, he said. ExxonMobil is conducting an official investigation into the incident's cause, he said.
Witnesses said the rotten-egg odor rolled westward from the island's east end to the island's middle before dissipating.
"The buildings sucked it all in, so by the time it cleared up outside, the smell was unbearable inside and classrooms were evacuated," said George Crozier, director of the Dauphin Island Sea Lab.
Crozier said dozens of people, including housekeeping staff, faculty and students, complained of sore throats, itchy eyes and nausea all symptoms of hydrogen sulfide exposure.
For those familiar with the Mobile County EMA's recommended response to such a danger, a warning of such a leak would mean closing up their homes and businesses and turning off air conditioners and closing vents. But no warning came.
"It appears to have been a complete breakdown in this fail-safe system we thought we had here on the island," said Bill Harper, president of the Dauphin Island Property Owners Association.
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Information from: Press-Register, http://www.al.com/mobileregister