Two aerial firefighting jets have been sidelined due to corrosion believed to be caused by a recently approved fire retardant used by the U.S. Forest Service in 2023.
Last year, two large air tankers deployed a magnesium chloride-based fire retardant while battling wildfires, leading to corrosion in critical areas of the aircraft, the Billings Gazette reports. The National Transportation Safety Board, National Institute of Standards and Technology, and the Forest Service are conducting a joint investigation into the issue.
The Forest Service, after discovering corrosion during winter inspections, opted against using the magnesium chloride retardant this year. Instead, they will rely on the longstanding ammonium phosphate fire retardant.
Developed by Fortress North America, the magnesium chloride product was touted as environmentally friendly, contrasting with ammonium phosphate, which faced legal action in 2022 for its adverse effects on aquatic habitats.
File Photo> An air tanker drops retardant onto the Gravel Pit Fire in Montana in August 2023. (Inciweb photo.)
Perimeter Solutions, the traditional provider of the Forest Service’s ammonium phosphate retardant, will continue its supply this year.
The two tankers affected are owned by Neptune Aviation in Montana and Erickson Erickson Aero Tanker in Oregon. Neptune told the Gazette it planned to have the jet operable for this fire season; Erickson said its jet would be out of service for 2024. Cost of repairs could run into the millions.
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