Model used to gauge tire-burning impacts flawed

By Matt Trebella

The model used for the environmental assessment for the Holcim tire-burning proposal was insufficient in size and scope to thoroughly examine the fate of pollutants. It is my opinion that a thorough review of the air dispersion model prepared on behalf of Holcim will show either gross negligence or planned deception.

The first issue is the size of the model. The model has a maximum of nine kilometers for pollution transport in any one direction. Other model calculations estimate that the peak concentration of large particles doesn't even occur until about 20 kilometers (nearly 13 miles). How can the Montana Department of Environmental Quality make informed decisions about the air quality, and possible violations of the Clean Air Act if they do not have this distance included in the model?

If one performs as mass balance on the information provided to the DEQ there is certainly missing mass, but where that mass has gone is not reported. This missing mass must be accounted for either in transport out of the model boundaries, or by deposition. In either case, there is the possibility that concentrations of pollutants will exceed those allowed by Montana laws.

Thus far the DEQ has seen inadequate modeling information to make intelligent decisions about the possible results of tire burning at the Holcim plant. I don't know if there will be violations of the Clean Air Act, or if pollutant levels will exceed those allowed by Montana laws, but until further modeling studies are conducted, nobody knows.

It is the responsibility of the DEQ to demand a full EIS be performed to address these and other issues, rather than trusting the data presented thus far on behalf of Holcim. The health of our economy, our environment, and our citizens, is far too important of a decision to base on such an inadequate and invalid computer model.

Matt Trebella

2506 Snapdragon St.

Bozeman

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