‘Major source’ of air pollution operated without permits for decades, DNR says
The Iowa Department of Natural Resources regulates the air emissions from manufacturing facilities. (Photo by Jared Strong/Iowa Capital Dispatch)
A Muscatine company that operates a large, gas-powered dryer to process sand that it sells has failed for decades to obtain permits to update and operate it, according to the Iowa Department of Natural Resources.
Northern Filter Media has operated just south of Muscatine for more than a hundred years, processing sand and gravel to be used in municipal water treatment plants and for other purposes.
In 1985, the company installed a new burner in its dryer. The dryer was subsequently renovated in 2002, 2017 and 2020, DNR records show.
“Northern Filter Media has operated the sand dryer unpermitted since its installation and the renovations,” according to a recent DNR order that fined the company $10,000.
Those permits are important to monitor and limit the amount of particulate matter and other pollution that is vented into the air.
“This place has been there since 1914, and this is the first time this has come up,” said Vince Brown, a manager at the facility. “We don’t know what to do. We don’t know what the process is.”
It’s unclear why the DNR did not act sooner to correct the situation. About 10 years ago, a DNR officer noticed thick, brown emissions coming from the facility, and the department required the company to test those emissions for compliance.
The facility passed the test, but there was a potential problem with the results that wasn’t identified until three years later, according to DNR documents.
When the DNR officer noticed the pollution in July 2012, he estimated its opacity at 81.5%. DNR staff are trained and certified to estimate how much light is blocked by the emissions. During the testing in September 2012, the estimated opacity was about 8.5%, which indicated the facility was emitting considerably less pollution at the time.
“DNR Field Office 6 will continue to periodically travel past your sand drying plant, and if plumes of opacity are observed, photographic documentation will be collected for evidence to support enforcement action taken by Iowa DNR against Northern Filter Media,” the DNR wrote to the company in July 2015.
Last year, during a routine audit of documents the DNR had collected about the facility through the years, the department determined that Northern Filter Media is most likely a “major source” of air pollutants under state rules and could be subject to permit requirements based on Title V of the federal Clean Air Act.
“It’s just one of those things that through further review, we determined that they could be subject to the Title V program,” said Brian Hutchins, a supervisor for the DNR’s Air Quality Bureau. “And then in digging into permit requirements, collecting information from the facility and discussions we had with them. Yeah, they, in fact, should have obtained construction permits, long ago.”
The department based its new determination about the severity of emissions on the 2012 testing data, and in a December 2021 letter to the company the DNR estimated that the facility has the potential to emit more than twice the minimum threshold to be classified as a major source of pollution.
In 2012, not long after the testing, the DNR sent the company a letter that said: “The emission rate for this source is considered in compliance.”
“We were in full compliance of anything that had to do with the DNR,” Brown said. “So we are unaware that we’re breaking any rules whatsoever at all.”
Brown further said steam accounts for a lot of the emissions, but DNR officers have disputed that.
“We explained that steam is white and has a definitive point at which it condenses out of site,” one officer wrote to the company in 2015, “and the brown plumes we observed trailed well away from the sand plant.”
Hutchins said the company is expected to submit construction permit applications for its equipment. Based on a review of those applications, the company might be required to monitor its emissions to determine whether they need a higher level of regulation.
“Once we received the permit applications for those construction permits, we’ll have more information as far as if there’s any kind of additional requirements that’ll be placed on them, beyond just maybe some additional monitoring and record keeping,” Hutchins said.
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