30 CFR § 57.6101
Areas around explosive material storage facilities.
(a) Areas surrounding storage facilities for explosive material shall be clear
of rubbish, brush, dry grass, and trees for 25 feet in all directions, except
that live trees 10 feet or taller need not be removed.
(b) Other combustibles shall not be stored or allowed to accumulate within 50
feet of explosive material. Combustible liquids shall be stored in a manner
that ensures drainage will occur away from the explosive material storage
facility in case of tank rupture.
[58 FR 69596, Dec. 30, 1993]