Automakers and environmentalists have long hailed fuel cells as a revolutionary technology that can reduce planet-warming tailpipe emissions, which account for a significant portion of the greenhouse gases released in the United States. After years of development, several models are now on the road, like the Toyota Mirai and the Honda Clarity FC.

The next challenge is building networks of hydrogen stations so owners can refuel their cars.

So far California has 30, enough to enable owners to drive throughout the state without worry of running out of hydrogen, and it intends to expand that to 100 by 2020. Sales of fuel-cell vehicles have been limited to the state so far.

The automakers are poised, however, to expand into the Northeast. Air Liquide, a producer of industrial gases, is working with Toyota to set up a chain of 12 hydrogen fueling stations stretching from New York to Boston; the first is expected to go into operation later this year. Locations will include the Bronx; Brooklyn; Hempstead, N.Y., on Long Island; Lodi, N.J.; Hartford; and Braintree and Mansfield, Mass.

The availability of hydrogen fuel will pave the way for the start of East Coast sales.

The Northeast is “the next critical step toward a much wider distribution of fuel-cell vehicles,” said Craig Scott, director of Toyota’s advanced technology group. The densely populated Northeastern states “in some sense could rival California as a market,” he said, adding, “As a region, they have very good sales potential.”

In March, Hyundai previewed a new fuel-cell sport utility vehicle that it plans to introduce next year.