“Principal source” of air pollution operated without a permit for decades, says Iowa DNR

(Photo from the Bloomberg News file)

A Muscatine company that operates a large, gas-powered dryer to process sand it sells has failed to obtain permits to update and operate for decades, according to the Iowa Department of Natural Resources.

Northern Filter Media has operated south of Muscatine for more than a hundred years, processing sand and gravel for use in municipal water treatment plants and for other purposes.

In 1985, the company installed a new burner in its dryer. The dryer was subsequently refurbished in 2002, 2017 and 2020, DNR records show.

“Northern Filter Media has operated the sand dryer illicitly since its installation and renovations,” according to a recent DNR order, which fined the company $10,000.

These permits are important to monitor and limit the amount of particulate matter and other pollution released into the air.

“This place has been around since 1914, and this is the first time this has appeared,” said Vince Brown, a manager at the facility. “We don’t know what to do. We don’t know the process.”

It is unclear why the DNR did not act sooner to rectify the situation. About 10 years ago, a DNR official noticed thick, brown emissions from the facility, and the department asked the company to test those emissions for compliance.

The facility passed the test, but there was a potential problem with the results that DNR documents said were not identified until three years later.

When the DNR official noticed the pollution in July 2012, he estimated the opacity at 81.5 percent. DNR staff are trained and certified to estimate how much light is blocked by the emissions. During testing in September 2012, the estimated opacity was about 8.5 percent, indicating the facility was emitting significantly fewer pollutants at the time.

“The DNR Field Office 6 will continue to drive by your sand drying facility on a regular basis and when plume plumes are observed, photographic documentation will be collected as evidence to support enforcement actions taken by Iowa DNR against Northern Filter Media,” the DNR wrote to the companies in the July 2015.

Last year, during a routine review of documents the DNR had collected about the facility over the years, the department determined that Northern Filter Media is most likely a “principal source” of air pollutants under state regulations and could be subject to permitting requirements based on Title V of the Federal Clean Air Act.

“It’s just one of those things that through further review we found could be subject to the Title V program,” said Brian Hutchins, a supervisor of the DNR’s Air Quality Bureau. “And then to investigate permitting requirements, gather information from the facility and have interviews with them. Yes, they should have received building permits a long time ago.”

The department based its new emission severity determination on the 2012 test 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 the main source to be classified of pollution.

In 2012, not long after the tests, the DNR sent the company a letter stating, “The emission rate for this source is considered compliant.”

“We were fully compliant with everything that had to do with the DNR,” Brown said. “So we’re not aware that we’re breaking any rules at all.”

Brown went on to say steam accounts for a majority of the emissions, but DNR officials have denied this.

“We explained that steam is white and has a specific point where it condenses offsite,” an official wrote to the company in 2015, “and the brown plumes we observed were far from the sand facility.”

Hutchins said the company expects to submit building permit applications for its equipment. Based on a review of these applications, the company may need to monitor its emissions to determine if they need a higher level of regulation.

“Once we receive the permit applications for these building permits, we will have more information as to whether there are any additional requirements that are placed on them, aside from perhaps additional monitoring and recording,” Hutchins said.

This article first appeared in the Iowa Capital Dispatch.