The United States Environmental Protection Agency (EPA) is investigating the apshalt concrete production source category to identify and quantify emissions of hazardous air pollutants (HAPs) from rotary aggregate dryers. Plant 'A', Clayton, North Carolina was identified and selected by EPA as the host facility at which no obtain data on air emissions from a counter flow continuous drum mix process that utilized a baghouse for control of air emissions. The primary objective of the testing program was to obtain data on controlled and uncontrolled emissions of polychlorinated dibenzo-p-dioxins (PCDDs or 'dioxins') and polychlorinated dibenzofurans (PCDFs or 'furans'), particulate matter (PM), and metallic HAP and non-HAP compounds. Testing of uncontrolled emissions was deleted from the scope of work because the high particulate grain loading at the inlet to the baghouse exceeded the sampling capacity of the Method 23 and method 29 sampling trains. A secondary objective was to observe and record plume opacity from the baghouse. The data will be used by the EPA's Emission Standards Division to determine whether HAPs are emitted at levels that would justify regulation under the Maximum Achievable Control Technology (MACT) program. During the testing program another EPA contractor monitored and recorded process and emission control system operating parameters, and prepared Section 3.0, Process Description, of this report.

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