The Winona Citizens' Environmental Quality Committee (EQC) discussed a concept for air quality monitoring in which the city would hire consultants to conduct testing for silica dust at frac sand facilities and sand companies would foot the bill. The committee did not make formal motions, but it was clear that the committee supported mandated monitoring and thought that companies should not hire consultants directly, but rather, the city should choose which outside firm would do the work. The committee discussed the issue following a request from City Council for a silica dust monitoring proposal.
The decision to support city-mandated monitoring came after some discussion. Initially, committee member Jon Nosek said, "Yes, we think air quality monitoring is a necessary component of the process. Personally, I'd be content to let the [Minnesota Pollution Control Agency (MPCA)] take the lead on that."
The MPCA is considering the issue of silica dust emissions at frac sand facilities and bills on the issue exist in the state legislature as well.
Committee member Bea Hoffman asked Assistant City Planner Carlos Espinosa what would happen if the EQC deferred to the MPCA and legislators. Espinosa replied that the city would regulate air quality using existing moisture testing rules.
"I think that's concerning," Hoffman said. The current moisture testing regulation does not require that sand on the surface of stockpiles be tested. Citizens at city public hearings have said that the surface of the piles is what matters because that is where any dust would become airborne.
The committee went on to discuss having monitoring conducted by an outside consultant at company expense and leaving many of the detailed questions of how to conduct monitoring up to the consultant. As Espinosa explained, "The resources and expertise for air quality monitoring lie with consultants and MPCA, the city does not have resources [for it]."
City Planner Mark Moeller summarized the consensus of the committee that this draft proposal would be "an interim ordinance until the MPCA develops a process."
It is unclear if the committee reached a consensus on the issue of what limit for dust to use. The state of California limit — which is three micrograms of crystalline silica per cubic meter of air averaged over a year — was discussed by the committee and has been discussed by City Council members. When Moeller asked the committee for clarification of what limit they were recommending, Nosek said, "I don't know if I see that as our choice to make."
However, other members of the committee voiced support for the California limit, and Espinosa confirmed that it would be included in the draft recommendation he is preparing for committee review.
City staff will prepare that draft recommendation for the committee to consider in May. If approved, the recommendation will be forwarded to the Planning Commission. In theory, an ordinance proposal could come before the City Council this summer.
Last month the council directed the Planning Commission to draft what council members called a "proactive" ordinance to monitor air quality at frac sand facilities rather than just wait for state action on the issue. The Planning Commission referred the issue to the EQC earlier this month.
The committee also supported conducting monitoring of diesel fumes along truck routes used by the frac sand industry, a step that several members of the City Council opposed when discussing air monitoring regulations. If adopted in the committee's recommendation, the monitoring of diesel exhaust would be separate from silica dust monitoring efforts.
Nosek pointed out that limits for acute exposures to ambient silica dust do not exist. The EPA has a 24-hour limit, but, according to Espinosa, 24-hour figures are averaged over a year. If the 98th percentile of that average exceed the the 24-hour limit, then it breaches the EPA standard, he explained. Nosek pointed out that there may be seasonal peaks to silica dust, such as during drouthy summer months, that could be of concern to residents.
Studies of silica dust emissions
The first studies on whether silica dust at frac sand facilities in the region breach limits considered to be a health risk are still underway. Studies have recently begun at a handful of sites in Minnesota. Espinosa included preliminary results from a Wisconsin study being conducted by a consultant hired by the oil and gas corporation EOG Resources, which indicates measured levels of dust do not exceed EPA limits.
"I'm uncomfortable with the industry hiring someone to do it," committee member Holly Lenz said.
In 2011, a study was conducted of air quality at mines and transport facilities in Winona by a consultant hired by Sierra Frac Sand of Texas. That study held that the sites were not emitting any dust. At the time, city staff referenced the study as evidence that dust was not being generated. MPCA air quality officials later decried the study for using equipment inadequate to detect dust and monitoring in a way that could not be compared to federal limits.
Dr. John Richards, who is conducting the Wisconsin air study, reports that he has followed all federal standards for monitoring equipment and procedures, and the Wisconsin Department of Natural Resources is reviewing the study.