Comment submitted by M. Hibbs

Dear sir or madam: Within the Prevention of Significant Deterioration (PSD), and during baseline measurements of 1977, Volatile Organic Compounds (VOCs) were defined as ?Tons of Carbon? by the capabilities of EPA Method 25A. Currently, VOC is measured as ?Tons of Carbon? converted to a surrogate hydrocarbon and added to that amount the speciated test results of ?Whole Molecule? weight to determine the total VOC emitted from a source in tons. This number should not be compared to PSD VOC (40) tons of carbon. NSR should not be triggered when VOC ?Whole Molecule? weight is compared to and exceeds PSD VOC ?tons of carbon?. The definition of VOC in respect to PSD is clearly defined as ?Tons of Carbon from all VOC measured?. Additionally, if EPA Method 25A is utilized to capture mixed VOC from a source and added to speciated tests for other compounds from the same source, then the response factor for those speciated compounds measured by EPA Method 25A must be backed out of the total VOC measured. Michael Hibbs mhibbs@proaxis.com