NEW YORK CITY-Mayor Michael Bloomberg on Thursday gave an update on PlaNYC, his initiative to create a greener, greater New York. One much celebrated part of the initiative calls for the phasing out of numbers 4 and 6 heating oils. One percent of buildings in the city, a PlaNYC press release says, “produce 86% of the soot pollution from buildings,” a figure that surpasses that created by all the cars and trucks here.

But some are concerned that costs for the initiative are going to be passed on to tenants. “It’s certainly a good idea over the long term,” Dan Margulies, the executive director of the Associated Builders and Owners of Greater New York, tells GlobeSt.com. “There is a significant cost in putting in a replacement burner or replacing a boiler that can range anywhere from $10,000 to $100,000.”

A city spokesman says that 10,000 buildings around the city will be affected by the new rule but that the phase out is staggered and meant to coincide with natural replacement schedules.