Exposure to impalement is a serious consideration when employees are  working above sharp objects like the pointed lightning rod. OSHA regulations recognize the risk of impalement and require protection for employees where impalement hazards exist. This recognized hazard has prompted the use of numerous ineffective methods of protecting personnel from roof mounted pointed lightning rods. Methods include the use of warning markers, acrylic tip covers, and in some cases the entire rod is covered with pvc conduit.  The use of these types of protectors can drastically reduce system performance while doing little to protect against impalement.

"Where a lightning rod poses a recognized hazard of impalement and there is a feasible means of protection, the employer is required to provide that protection."

Excerpt from letter written by Directorate of Construction for the U. S. Department of Labor's Occupational Safety and Health Administration