(a) Liquid hydrocarbon fuels with flash points lower than that of No. 2 diesel oil (125 oF) shall not be used to prepare ammonium nitrate-fuel oil, except that diesel fuels with flash points no lower than 100 oF may be used at ambient air temperatures below 45 oF.
(b) Waste oil, including crankcase oil, shall not be used to prepare ammonium nitrate-fuel oil.
053-2 Wyo. Code R. § 56.6309