Businesses across the U.S. are reevaluating security after a shooting at a New York City office building raised concerns about workplace safety. The attack on a seemingly secure tower left four people dead and has companies desperate to prevent similar incidents. Security firms around the country say they're getting a spate of calls from corporations anxious to make sure the measures they have in place are adequate. The building where the attack happened — 345 Park Avenue in midtown Manhattan — did have security systems in place. An off-duty New York Police Department officer was working as a guard there, but was among the victims of the attack.