New rules in effect for wood-fired boilers

(Victoria Arocho for The Boston Globe)

The boilers sit away from the house. But some say the smoke they produce is potentially harmful

By Globe Staff

Outdoor wood-fired boilers, which have sparked controversy in some parts of New England because of the smoke they spew, will be regulated more tightly, under new regulations that go into effect today in Massachusetts.

Massachusetts is one of only a few states that restrict pollution from such boilers, which are also known as outdoor hydronic heaters, state environmental regulators said.

Outdoor boilers are located in small, insulated sheds with smokestacks usually six to 10 feet tall. They burn wood to heat water that can then be piped to buildings, greenhouses, and swimming pools, the Department of Environmental Protection said.

Critics say the devices are noxious because they restrict air flow in order to slow combustion, the Globe reported in November. While the restriction allows wood to burn longer, it also builds up large amounts of soot and creosote, which are periodically released in billowing plumes that air quality officials say are potential health hazards.

Under the regulations, only heaters that meet a new standard for particulate emissions can be sold in the state. The regulations also include a variety of rules for new and existing units, addressing issues such as setbacks from property lines, smokestack heights, what can be burned, and when the boilers can be operated.