Iowa DNR: Ethanol plant pollution likely harmed public health for years near Shell Rock

By Jared Strong

An ethanol-producing facility in northeast Iowa expelled excessive pollutants into the air for several years that can cause cancers and other health effects, according to the Iowa Department of Natural Resources.

“Actual harm to the environment and public health likely occurred,” the department said in a recent administrative order regarding POET Bioprocessing near Shell Rock.

The facility makes about 140 million gallons of ethanol each year, along with other products from the leftover materials of the fuel production.

The excessive pollution was tied to one of those additional products: a protein ingredient for animal feed.

The facility’s previous operator, Flint Hills Resources, installed the equipment that is used to extract the protein and began operating it in July 2020, the DNR order said. However, part of the system lacked sufficient pollution controls, which was discovered by POET in August 2023. POET had purchased the facility about two years earlier, but did not sample the emissions.

Flint Hills had underestimated the amount of pollutants in the ethanol-production leftovers that are used to produce the protein, said Mark Fields, a unit leader for the DNR’s Air Quality Bureau. Those pollutants were then expelled during the protein processing.

Fields said the issue was discovered with a similar system in another state, and POET shut down the production line and notified the DNR. The company later routed those emissions into an existing pollution-control system at the plant and fixed the problem.

But emissions tests after the production line was reactivated revealed the extent of the excessive pollution in the previous years: Its volatile organic compounds emissions were 27 times its permitted limit, and emissions of a hazardous, cancer-causing compound — acetaldehyde — were nearly nine times the limit.

The POET facility lies about two miles northwest of Shell Rock, and about five miles west of Waverly.

POET agreed to pay a $10,000 administrative fine, the DNR order said. It also will pay nearly $43,000 in fees that it owed the state for its underreporting of emissions in 2021 and 2022.

The company did not immediately respond to a request to comment for this article.

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