The EPA will start from a blank slate as it weighs whether and how to limit refrigerant chemicals that are potent greenhouse gases, but it’s unclear if the agency will provide the long-term certainty industry is seeking.

The Environmental Protection Agency said in new guidance that it won’t implement a series of Obama-era regulations restricting the production and use of hydrofluorocarbons, or HFCs—chemicals often used as refrigerants that have a global warming potential hundreds to thousands of...