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Correspondence



November 1, 2000

AR-18J
Lynn Fiedler, Chief
Permits Section, Air Quality Division
Department of Environmental Quality
P. O. Box 30260
Lansing, Michigan 48909

Dear Ms. Fiedler:

I am writing to submit United States Environmental Protection Agency’s comments and questions on Permit to Install Number 134-99A for General Motors Corporation (GM) Lansing - Grand River plant located in Lansing. GM is proposing to increase recently permitted limits for the topcoat system and the ELPO dip tank. In addition, GM is adding a foam process and changing the setup of certain systems without affecting emissions. The public comment period for this permit ends November 1, 2000.

Comments

1) Special Condition 12 limits the production rate to 38 jobs per hour. The underlying applicable requirement for this condition is listed as R336.1225. Although from the application, it appears that GM relied on this production rate in determining best available control technology and 112g. Therefore, the condition should site all of the underlying applicable requirements along with R336.1225.

2) On page 14, the application states that GM believes that the 30 percent VOC loading in the heated flash is aggressive and may not reflect what can be achieved in practice. As a result, GM has based its revised emissions using a VOC loading to the heated flash of 15 percent in its revised calculations. However, during the public comment period for the original permit, EPA commented that GM should do additional cost analyses. At that time, GM increased the loading from 10 percent to 30 percent. This increased the cost per ton of add on controls for the basecoat line to an amount considered economically infeasible. At that time GM felt confident that this 30 percent was achievable. We have several questions concerning GM decreasing the loading that we would like considered and if no satisfactory answer exists, Michigan should modify the permit accordingly. What specific data is now available that no longer supports using 30 percent, and how is this different from the data available during the original permitting process? Why was this data not available during the original permitting process? What data did GM rely on during the original permitting process to increase the loading up to 30 percent, and why is this data no longer reliable?

3) Also on page 14 of the application, GM has provided the square feet of the surface area by coating zone. The original permit assumed 224.4 square feet of surface area to be painted. The final design is assuming 244 square feet for the basecoat zone and 221 square feet for the clearcoat zone. Since the surface area of a car should remain the same, please address why a larger surface area is being coated for the basecoat than for the clearcoat? If no justification can be made, the surface area and all calculations based on the current inconsistent surface areas must be corrected. In addition, GM has failed to address in the permit application how this increase in surface area will effect the emissions from the other coating lines. For example, how will increasing the surface area of the car not increase the emissions of the primer and ELPO lines? This should be addressed before issuing this permit.

If any emissions change based on these comments, the cost analysis should be updated to reflect these changes. If you have any questions, feel free to call Laura Hartman at (312)353-5703.

Sincerely,

\s\

Robert Miller, Chief
Permits and Grants Section (MI/MN/WI)





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