ROCK SPRINGS, Wyo. (AP) - An investigation continued into the death of an oilfield worker who fell 90 feet from a drilling rig.

Phillip Pepper, 43, died Wednesday night after falling from a rig about 70 miles northeast of Rock Springs, according to Sweetwater County Sheriff Dave Gray.

Pepper, whose hometown was not available, was an employee of True Drilling of Casper.

"We don't know what caused him to fall or allowed him to fall from the crow's nest," Sheriff Dave Gray said.

State worker safety investigators were looking into the incident, Gray said.