The Iowa Department of Natural Resources is investigating a spill of lactic acid from a semi truck on Interstate 80, east of Adair, that flowed through storm drains and into a tributary of the South Fork Middle River.
According to a press release from DNR, the semi driver was headed east on the interstate and pulled over after noticing the tires were smoking.
The driver attempted to put out the fire while stopped at a rest stop about three miles outside of Adair, but was unsuccessful. By the time the Adair Fire Department arrived, the trailer and its contents, including poly totes full of lactic acid the trailer was hauling, were on fire.
Alison Manz, a senior environmental specialist with DNR, said the water used in firefighting activities mixed with the lactic acid that had spilled from the totes and then flowed into two storm drains and into nearby farm ground.
The mixture flowed about 200 feet through the farm before entering a tile intake that released into an unnamed tributary of the South Fork Middle River, according to the DNR release.
Manz said a very acidic substance in a waterway can result in fish kills, though none have been observed.
It is estimated that 550 gallons of lactic acid were lost from the totes. The Iowa Department of Transportation also responded to the incident and tried to contain the spill with sand.
The fire occurred on Tuesday and by Wednesday afternoon, Manz said a hazmat response company, covered by the trucking company’s insurance, had cleaned up all of the remaining totes from the site.
Manz said the same team will neutralize the area with soda ash, flush the area and the storm drains with water that will be collected, and either excavate the affected soil in the farmland or neutralized it with ag lime.
According to the Iowa DOT website, as of Wednesday afternoon, the rest area remains closed. DNR advised downstream users, including those watering cattle, to avoid the area.
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This article originally appeared on Des Moines Register: I-80 semi fire leads to spill of estimated 550 gallons of lactic acid