PALM HARBOR, Fla. - A 58-year-old man was killed Wednesday morning after being pinned by the sign he was working on, the Pinellas County Sheriff's Office said.

Robert Tanner, of Tarpon Springs, was in a bucket attached to a hydraulic boom that was about 20 feet in the air in front of Glory Days Grill on U.S. Hwy. 19 when he leaned over the boom's control panel switches while attempting to reach an electrical access panel on the sign, authorities said.

In doing so, Tanner's body inadvertently activated the switches, causing the boom to rise upward, authorities said.

"The upward motion of the boom pinned Tanner's torso between bucket and the metal overhang of the sign," the department said in a statement. "Tanner was unable to release the switch due to the hydraulic pressure."

Charles Walker, Tanner's co-worker on the ground, tried to reverse the boom by accessing a control panel on the side of their truck, but was unable to reverse the hydraulic pressure or override the control panel, authorities said.

Paramedics spent more than 20 minutes working to free Tanner from the bucket.

Tanner was pronounced dead at the scene.

The incident appears to be accidental, but the investigation is ongoing, authorities said.

Both men were employees of Accent Neon and Sign Company.

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