Appliance manufacturers and chemical makers have had enough of the Trump administration’s silence on a global deal to reduce climate-warming coolants, and they’ve got a message for the EPA: Speak up.

For months, the U.S. refrigeration and chemical industries have quietly lobbied the Trump administration to support a 2016 global agreement to phase down hydrofluorocarbons, or HFCs, refrigerant chemicals that are highly potent greenhouse gases. And though a State Department official offered tentative backing for the deal late last year, it’s unclear if the industry is any closer to convincing the president to send the pact to the...