the USGBC issued the following ruling: “Project teams may classify duct sealants under “Other”, as listed in the SCAQMD VOC Limits table.”
The category of “Other” in the SCAQMD VOC Limits table has a maximum limit of 420 g/l. This should allow most if not all duct sealants to be utilized on LEED® projects, and permit the proper sealing of ductwork at temperatures below 40°F (5°C).

http://www.smacna.org/technical/download.cfm?download_file=TRB9-09-Updat...