The courier knew she was going to pick up a large amount 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. As she was driving to the physician 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 started raining.
While driving down the road a little later, the courier was suddenly overcome with a feeling of sleepiness. Before she realized what could be wrong, she lost consciousness and the vehicle swerved off the road.