Two painters died late Wednesday morning when their boom lift tipped over at the Lower Buckeye Jail in Phoenix.

The lift, owned by H&E equipment, was parked on a hill and the men were painting a six-story building, said Lt. Brandon Jones, a spokesman for the Maricopa County Sheriff's Office. The lift had been placed on a downhill slope on the jail's northwest side. The men were working for Riddle Painting and Coating, a contracted vendor.

Inmates in the recreation yard of the county jail facility saw the painters fall and reported it to correctional officers. The men were transported to a Phoenix hospital where they were pronounced dead.

The jail facility is at 3250 W. Lower Buckeye in Phoenix, at the corner of 35th Avenue. The accident remains under investigation, and the men's names have not yet been released.

Both the Occupational Safety and Health Administration and the American National Standards Institute have a series of rules designed to protect employees using aerial lifts. Language in the code requires level, improved surfaces for the operation of high-lift industrial trucks.

A Bureau of Labor Statistics study which assessed aerial lift accidents in the construction industry from 1992 to 1999, revealed 64 deaths from falls, including 35 that were the result of falls from boom-type lifts. The same study showed that painters suffered 8% of fatalities, trailing electricians, laborers and electrical power installers.

According to more recent U.S. Bureau of Labor Statistics data, the construction industry had the most deaths of any industry in 2012, at 775, with 232 coming from falls. The fatality rate for the construction industry in 2012, however is 9.5 per 100,000 workers which trails the agriculture, mining and transportation industries. There were 37 fatal work injuries from all industries in Arizona in 2012.