In anticipation of summer thunderstorms, OSHA and NOAA have issued a Fact Sheet on Lightning Safety when working Outdoors. (In case you were curious, the slogan above comes from NOAA, who advises “that nowhere outside is safe when thunderstorms are in your area.”).
The Fact Sheet encourages employers to recognize lightning as an occupational hazard and put safety protocols in place for employees whose jobs involve working outdoors in open spaces, on or near tall objects, or near explosives or conductive materials (e.g., metal). Suggested lightning safety best practices include: checking NOAA weather reports; seeking shelter in fully enclosed buildings or, if none accessible, in hard-topped metal vehicles with rolled up windows; avoiding use of “corded phones.”
The Fact Sheet is here: https://www.osha.gov/Publications/OSHA3863.pdf