According to Sheriff Ed Gonzalez, the crash happened in the area of U.S. 90 and FM-2100 just outside of Crosby.
"An adult male pedestrian, struck by an 18-wheeler, has been pronounced deceased at the scene," a tweet by Gonzalez read.
Authorities later confirmed the victim was part of a debris cleanup work crew in the area.
U.S. 90 is closed just east of FM-2100. It's not immediately known how long the roadway will remain closed.
SkyEye over the scene spotted the big rig stopped on the side of the road.
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