Half of employers with 1,000 employees or more in the United States had an incident of workplace violence in 2006, the Bureau of Labor Statistics reported in a study conducted for NIOSH.

The survey asked whether an incident of workplace violence had occurred during the past year and, if so, how the incident had affected the staff and had the employer implemented changes to reduce the risk of further incidence.

While 5 percent of all establishments, including state and local governments, had a violent incident, half of the largest establishments (employing 1,000 or more workers) reported an incident.

More than 34 percent of employers with 1,000 or more workers said they had a co-worker incident within the 12 months before completing the survey. More than 28 percent of large employers said they had a customer or client incident. More than 24 percent said they had a domestic violence incident. And more than 17 percent said they had a criminal incident.

Of all establishments reporting an incident of workplace violence in the previous 12 months, 21 percent reported that the incident affected the fear level of their employees, and 21 percent indicated that the incident affected their employees' morale.

According to Business & Legal Reports, over 70 percent of United States workplaces have no formal program or policy that addresses workplace violence.