Which agency provides safety standards for gas appliances?

The American National Standards Institute (ANSI) is the agency that provides safety standards for gas appliances, making it the correct choice. ANSI is responsible for developing and promoting standards for various industries, including those related to gas appliances. These standards ensure that appliances are safe for consumer use, reducing risks of accidents, fires, and other hazards associated with gas equipment.

While other organizations like the Environmental Protection Agency (EPA) focus on environmental regulations, including emissions and pollution control, and the Occupational Safety and Health Administration (OSHA) is concerned with workplace safety and health regulations, ANSI specifically addresses the safety standards required in the manufacturing and operation of gas appliances. The National Fire Protection Association (NFPA) is also involved in fire safety codes and standards, yet does not specifically provide the broad range of safety standards that ANSI develops for gas appliances. Thus, the focus of ANSI on comprehensive safety standards relevant to gas appliances is the reason it is the correct answer.