Tiller Corp. penalized for air quality violations


The Minnesota Pollution Control Agency has reached an agreement with Tiller Corp., resolving air-quality violations at the company’s sand-processing facility in North Branch, according to a press release by the MPCA.

The agreement covers the company’s failure to obtain required air-quality permits before starting construction of the North Branch facility in late 2011. Tiller Corp. has not yet begun operating the facility, so there have not been any emissions that needed to be covered by limits set forth in the permit. Nonetheless, starting construction without permits is a violation of state and federal air-quality laws.

Tiller Corp. operates a sand mine in western Wisconsin, and sought to build an industrial facility for processing and shipping sand in North Branch. Because the facility has the potential for air emissions above state and federal thresholds requiring air-quality permits, the company was required to apply to the MPCA for the proper permits before beginning construction but failed to do so.

The company first submitted an application for an air-quality permit called a Part D Registration permit in February 2012. Registration permits provide coverage for specific industrial sectors, to which facilities with lower emissions may apply to be covered under state rules. However, the application was rejected by the MPCA because the potential emissions triggered requirements for an individual permit under the federal Clean Air Act.

Both permits require project proposers to apply for and receive the proper permits before starting construction.

The company applied for an individual permit in April 2012, which the MPCA placed on public notice from Nov. 8 to Dec. 14, 2012. The MPCA is considering public comments received during the notice period and expects to issue the permit soon. Until the permit is issued, the company may not operate the facility.

To resolve the violations the company agreed to pay a civil penalty of $5,000 and perform a Supplementary Environmental Project (SEP) valued at not less than $14,800. The SEP consists of air monitoring for particulate matter at the site for a period of two years. Monitoring will be conducted for particulate matter of three different sizes ─ PM10, or particles sized 10 microns or less; PM4; and PM2.5. There are state and federal standards for PM10 and PM2.5 in ambient air. There are no current standards for PM4, however that is the particle size of most interest to public health agencies concerned with potential health effects at industrial facilities where silica sand is mined or processed.

As the MPCA has dealt with public concern over the proliferation of silica sand facilities in the last couple of years, data have been lacking on particulate concentrations in ambient air at or near these facilities. MPCA officials said including the monitoring SEP as part of this enforcement action should provide data that will be very useful in permitting other facilities. It will also help measure whether the facility is impacting local air quality.

“This enforcement case provided a great opportunity to obtain monitoring data that the state needs to have assurances about the potential impact of these facilities on the environment and public health,” MPCA Industrial Division Director Jeff Smith said. “The company was quite willing to do it. They’ll conduct monitoring using MPCA-approved protocol for a minimum of two years, and will submit the data to us semiannually as part of their other required emissions reporting.”

When calculating penalties, the MPCA takes into account how seriously the violations affected the environment, whether they were first-time or repeat violations, and how promptly they were reported to appropriate authorities. Penalties also attempt to recover the calculated economic benefit gained by failure to comply with environmental laws in a timely manner.  SEPS may be substituted for monetary penalties where the SEP can provide a significant environmental benefit to the state and the company is willing to undertake the project under MPCA oversight.

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