6 CFR Part 27: Clarification to Chemical Facility Anti-Terrorism Standards; Propane [open pdf - 51KB]
"This notice clarifies how certain provisions of the Chemical Facility Anti-Terrorism Standards (CFATS) apply to the Chemical of Interest (COI) propane, which the Department of Homeland Security (DHS or Department) understands to contain at least 87.5% of the chemical propane. Specifically, this notice clarifies how the Screening Threshold Quantity and certain counting rule provisions apply to the COI propane."
Government Printing Office: http://www.gpoaccess.gov/fr/
Federal Register (March 21, 2008), v.73 no.56, p.15051-15052