Abstract: On Sunday, August 19, 2012, Employee #1 was working as a highway maintenance lead worker for the California Department of Transportation, or Caltrans. He was engaged in highway, street, and bridge construction and maintenance. Employee #1 started work at about 6:30 a.m. that day in the Mojave area shop, changing blades on a grader. From there, Employee #1 went to a highway worksite, arriving at approximately 11:30 a.m. He was the lead worker there, acting as the supervisor in charge of the project to repair the number two westbound lane on I-58 south of California City, CA. He was working in high heat conditions, assisting in the repair of a stretch of highway. All the workers on the site performing the road repair worked directly for Caltrans. Most of the work was performed from air conditioned equipment. The employees had sufficient water, shade, and training. The grader was knocking off the high spots on the road in preparation for paving. After the grader leveled the road, a sweeper followed to pick up most of the debris. Employee #1 was performing some intermittent shovel and broom work. Employee #1 had an air conditioned truck, and he was taking breaks in it throughout the job. The repair work was completed at approximately 3:00 p.m. Following that, the cones were picked up, and the workers finished at approximately 5:00 p.m. The recorded high temperature for that area that day was 100 degrees Fahrenheit. Employee #1 did not feel any heat illness symptoms that day while working or upon leaving. He did not tell anyone else about any heat illness symptoms either. At about 4:30 a.m. on Monday, August 20, 2012, Employee #1 was taken to the hospital from his home after vomiting and feeling symptoms of dizziness, fatigue, weakness, and nausea. Employee #1 had personal risk factors that contributed to heat exhaustion. The incident was reported by the employer to the Bakersfield District office at 2:12 p.m. on August 20, 2012.