Over the past several years, personal protective equipment (PPE) has been developed to protect workers from the intense radiant heat energy of an electric arc flash event. Oberon arc flash suits, including hoods and hood shield windows, are available with heat protection levels up to 100 cal/cm2. However, there is increasing concern among some members of the NFPA 70E Technical Committee regarding potential hazards other than heat exposure that are also part of an electric arc event, e.g. shrapnel, pressure waves and high sound levels. The NFPA 70E Technical Committee elected to limit its Hazard/Risk Category exposure levels to 40 cal/cm2 in the proposed 2004 edition until a better understanding of these additional arc flash hazards is achieved.