172.502—Prohibited and permissive placarding.

[Amdt. 172-123, 55 FR 52599, Dec. 21, 1990, as amended at 56 FR 66259, Dec. 20, 1991; Amdt. 172-151, 62 FR 1230, Jan. 8, 1997; 62 FR 39389 and 39407, July 22, 1997; 66 FR 8647, Feb. 1, 2001; 66 FR 33426, June 21, 2001; 67 FR 53137, Aug. 14, 2002; 68 FR 75741, Dec. 31, 2003]