An oil worker died last week on a rig in Johnson County. Twenty-five year old Joshua Adam was killed Thursday at an Anschutz Corporation well site near Gillette. He was working for Texas-based contractor Basic Energy Services.

Hayley McKee, a spokeswoman for the Wyoming Department of Workforce Services, writes in an email that the incident happened during a well servicing operation. Adam’s death was caused by “an unexpected vertical movement of an oil derrick.” He died on site.

The incident is the first oil and gas worker fatality in Wyoming this year. In 2014, at least three oil and gas workers died in the state.