Silver Bay Seafoods CEO Rich Riggs says the facility was back in production shortly after midnight, about 4 hours after employees first discovered the leak and shut things down. Riggs says most of the ammonia was vented to the outdoors, and workers were evacuated from their dorms primarily as a safety precaution.
“In the meantime,” he said, “Engineers shut down the refrigeration system and isolated the relief valve by using a redundant relief valve. These systems are designed to have redundancy. Once the redundant relief valve became the primary valve, it completely secured the system.”
Silver Bay released less than 100 pounds of anhydrous ammonia in the incident – below the federal reporting requirement. The material is a gas at normal atmospheric pressure, and dissipated rapidly.
Sarah Moore, with the state’s Division of Spill Prevention and Response, says there was no threat to public safety. Nevertheless, anhydrous ammonia can be quite hazardous.
“Primarily it’s an irritant. So if it gets on your skin it can cause corrosive burns. It’s damaging along the same lines to your respiratory system. It can inflame the skin within your lungs and your respiratory system. And at high enough concentrations, it can be fatal.”
Moore says that approximately 240 employees were evacuated from the site, a higher number than the 150 estimated by the Sitka Fire Department. The fifteen employees taken to local hospitals had developed symptoms of anhydrous ammonia exposure. Two employees also received treatment for other injuries. Everyone had been released by 12:30 AM.
Silver Bay’s was the fourth ammonia leak in three years in the region. Wrangell Seafoods released ammonia in March of 2008; Icicle Seafoods in Petersburg experienced an ammonia scare in January 2009. Later that same year, in September, a power failure in Pelican forced the state to take emergency measures to remove the ammonia from the defunct processor there.
Moore says these risks come with the territory, and Silver Bay apparently managed them well.
“Anytime that you’re keeping a gas under pressure there’s the opportunity for a spill. And it’s not uncommon for there to be small releases. Silver Bay Seafoods did everything right according to their company plan, evacuated the plant when they realized they had a leak, and everybody’s okay.”
Rich Riggs echoes Moore’s sense of relief. He’ especially grateful to Sitka’s EMS personnel, fire department, mountain rescue, and the Coast Guard for their professional response to the situation.
“You always plan and train for events, but it’s the people on the ground that actually pull it off. You’re dealing with realtime events, whereas a training exercise, you don’t have the specifics, you’re just generalizing. I certainly appreciate the involvement and the responsiveness of all those entities.”
Silver Bay Seafoods is one of three large processors in Sitka. It also operates facilities in Craig and Valdez.
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