The courier knew she would pick up a large number of frozen specimens at the office, so she filled her large cooler with dry ice (approximately 8 pounds) before leaving the lab. She closed the cooler tightly and placed it in her vehicle. While driving to the physician's office, she heard a noise that startled her as the top of the cooler popped open in the back seat. She kept her windows closed because it looked like it might start raining.
The courier was suddenly sleepy while driving down the road a little later. Before she realized what could be wrong, she lost consciousness, and the vehicle swerved off the road.