Final answer:
The DOT and IATA regulate the transport of certain refrigerants, specifically dry ice (solid CO₂) and nitrogen. Both are used for their cooling properties and are considered dangerous goods requiring regulated transport. The correct answer is option: a) dry ice and nitrogen.
Step-by-step explanation:
The U.S. Department of Transportation (DOT) and the International Air Transport Association (IATA) regulate the shipping and transport of certain refrigerants. The correct answer to which refrigerants are regulated by the DOT and IATA is: a) dry ice and nitrogen.
Both dry ice, which is solid carbon dioxide (CO₂), and liquid nitrogen are used in various cooling applications due to their low temperatures. Dry ice sublimes at –78°C, providing cooling without melting into a liquid.
Meanwhile, liquid nitrogen is used due to its very low boiling point of –196°C, which makes it a potent coolant, particularly for transporting items that need to be kept at very cold temperatures.
The transportation of these materials is strictly regulated because they are classified as dangerous goods due to their low temperatures and the risks associated with handling them.