WINTHROP — The Minnesota Pollution Control Agency (MPCA) has fined the Winthrop Heartland Corn Products (HCP) ethanol plant $11,200 for failing emission stack tests.

Tests in November 2021 and February 2022 showed the company emitted volatile organic compounds and particulate matter above what is allowed by its permit, according to an April 25 MPCA news release.

A carbon dioxide scrubber failed an emission stack test for emitting volatile organic compounds that were 37% above the permitted limit.

An investigation confirmed that due to a misinterpretation of pretest numbers, scrubber operating levels were set too low. Two months later, a stack test demonstrated compliance.

A filtering bag-house also failed a stack test for emitting small particulate matter (PM 10) and very small particulate matter (PM 2.5) at a rate of 120% above permitted limits.

Additional investigation showed one of the bag-house bags was not properly installed, leading to a decrease in the control efficiency of the bag-house. The company corrected the problem and a stack test the following month demonstrated compliance.

In addition to paying an $11,200 civil penalty, HCP completed all required corrective actions.