Texas Natural Resource Conservation Commission Austin Texas Memorandum To: Permit Division Directors/Permit Engineers From: Lawrence E. Pewitt, P. E., Director, Permits Program Date: August 21, 1991 Subject: BACT or NSPS Requirements In some cases, either BACT requirements or NSPS requirements will result in a different opacity limit for the various emission points related to the facilities proposed for construction. In these cases, please be specific as to the opacity limit for each emission point and not rely on a reference to a NSPS limit or a general opacity limit. This should be of assistance to our investigators in determining compliance with opacity limits for each emission point.