Last Tuesday the Winona Citizen's Environmental Quality Committee (EQC) recommended that the city conduct air quality monitoring at frac sand facilities while it waits to see how and whether the state will regulate silica dust. The EQC recommendations call for the city to hire air quality monitoring consultants to conduct monitoring of silica dust at all mines, processing and shipping sites. The EQC recommends that these consultants be hired by the city but that the respective companies be billed for the work.
A quote given to the city by an air quality consultant estimated that year-long monitoring for one site would cost more than $46,000. Assistant City Planner Carlos Espinosa said that, if enacted, air quality monitoring regulations would probably take the form of changes to the performance standards in the zoning code. Such a change, he said, would apply to both new and existing businesses anywhere in the city.
The impetus for monitoring is health concerns about silica dust particles that are four micrometers in diameter or smaller (PM4), which are listed as carcinogens by the Occupational Safety and Health Authority (OSHA) and the World Health Organization (WHO). Another potential risk of silica dust of that small, respirable size is silicosis, the formation of debilitating scars on the lungs caused by silica dust. Based on his research of the issue, Espinosa explained, "What health experts are saying is that PM4 [silica] particles are where the most critical toxic effects for silicosis and cancer are thought to occur."
The committee also recommended that the city conduct baseline monitoring of particulate matter that is 2.5 micrometers in diameter or smaller (PM2.5) along city truck routes. Dr. Holly Lenz championed this recommendation, which is aimed at providing a baseline for comparing levels of diesel fumes in the air along truck routes. The WHO also lists diesel fumes as a carcinogen, concerned citizens have often pointed out. Lenz explained that when it comes to diesel fumes, PM2.5 is the size to be concerned about. City Council members discussed requiring monitoring of diesel fumes in tandem with requirements for silica dust; however, the monitoring of diesel fumes was dropped from the air quality monitoring proposal by council member Pam Eyden, who made the proposal, after other councillors objected.
A baseline refers to preexisting levels of particulate matter against which future changes in levels can be compared. Lenz and her fellow committee members recommended such monitoring in order to measure any increase in diesel fumes given off by increased truck traffic from frac sand facilities.
The committee recommended using the Minnesota Pollution Control Agency (MPCA) as a resource in conducting interim monitoring. The first point in their recommendation states that "a final decision on air quality monitoring standards should be determined by the MPCA." Committee members proposed adding language to specify that this recommendation was in tandem with a recommendation that city-run, interim monitoring should nevertheless begin as soon as possible. Espinosa advised the committee that this point was already included in separate recommendations.
In initial advice and briefings prepared for the EQC, city staff recommended waiting for the MPCA to decide how to regulate silica dust. That sentiment was also voiced by several members of the Planning Commission when the commission referred the issue to the EQC in April. Conversely, the Winona City Council called for "preemptive" action rather than waiting for state regulation when it referred the issue to the Planning Commission in March.
The Planning Commission is expected to take up the issue in two weeks and provide its recommendation to the council for a final decision this summer.
The EQC's recommendations are:
1. We recommend monitoring [of ambient, airborne silica dust] but defer to the MPCA for protocols, expertise, and resources. A final decision on air quality monitoring standards should be determined by the MPCA.
2. The city of Winona should conduct interim monitoring of crystalline silica if action to commence monitoring is not immediately available from the MPCA.
3. Interim monitoring should commence as soon as possible and use an annual average of 3 micrograms per cubic meter PM4 as a limit for ambient crystalline silica exposure at facilities.
4. Any firm hired to complete interim monitoring should be selected and hired by the city of Winona in consultation with the MPCA.
5. Any cost associated with monitoring should be paid by the industry.
6. Interim monitoring should also include baseline PM2.5 monitoring along truck routes.