10 C.F.R. § 850.38 – Warning signs and labels.

(a) Warning signs. The responsible employer must post warning signs at each access point to a regulated area with the following information:
DANGER BERYLLIUM CAN CAUSE LUNG DAMAGE CANCER HAZARD AUTHORIZED PERSONNEL ONLY
(b) Warning labels.
1. (1) The responsible employer must affix warning labels to all containers of beryllium, beryllium compounds, or beryllium-contaminated clothing, equipment, waste, scrap, or debris.
2. (2) Warning labels must contain the following information:
  DANGER CONTAMINATED WITH BERYLLIUM DO NOT REMOVE DUST BY BLOWING OR SHAKING CANCER AND LUNG DISEASE HAZARD
(c) Warning signs and labels must be in accordance with 29 CFR 1910.1200, Hazard Communication.