The US Federal Trade Commission, which regulates advertising in the US, is investigating America’s burgeoning carbon offset market and whether it is subject to greenwashing and misleading advertising.

Companies and shoppers in the US spent over $54 million last year on offset credits toward tree planting, wind farms, solar plants and other projects. As more companies use offset programs to create an environmental halo over their products, the commission said it was growing increasingly concerned that some green marketing assertions were not substantiated.

With the rapid growth of green programs like carbon offsets, “there’s a heightened potential for deception,” said Deborah Platt Majoras, chairwoman of the commission.

“Is there green substance behind the green sparkle?” said Daniel C. Esty, director of the Center for Business and the Environment at Yale University and author of “Green to Gold,” a book about how companies use environmental strategies to their advantage. “The carbon market is a leading example of the challenge of making sure that when people put their money into what they hope will improve their planet, that there is real follow-through.”