Fuels with sulfur content greater than that allowed by this Subpart may be fired when the facility owner can demonstrate that sulfur dioxide emissions do not exceed the value for S calculated using the following equation: S = (1.1AM + 2BT)/(M + T)

where:

S = Allowable sulfur dioxide emission (in pounds per million Btu)

A = Sulfur in oil allowed by section 225-1.2 of this Subpart (in percent by weight)

B = Average sulfur in solid fuel allowed by section 225-1.2 of this Subpart (in pounds of sulfur per million Btu gross heat content)

M = Percent of total heat input from liquid fuel including waste oil

T = Percent of total heat input from solid fuel (including coal, coke, wood, wood waste, and refuse-derived fuel)

Fuel mixtures and equivalent emission rate variances only apply to processes or stationary combustion installations. Compliance will be based on the total heat input from all fuels fired, including gaseous fuels and waste oil. Any process or stationary combustion installation owner who chooses to fire a fuel mixture pursuant to this subdivision is subject to the emission and fuel monitoring requirements of section 225-1.5 of this Subpart.

Upon application, the department may issue a variance allowing the sale, offering for sale, purchase and firing of fuel having a sulfur content in excess of the limits imposed by this Subpart, where such fuel would be fired to demonstrate the performance of experimental equipment and/or process(es) for reducing sulfur compounds from an emission source.

In New York City and Nassau, Rockland and Westchester Counties, the commissioner will permit the sale and the continued, but not increased, purchase and use of coal and coke for installations with a maximum operating heat input equal to or less than one million Btu per hour if coal and coke has been used continuously since December 31, 1967 and the maximum sulfur content does not exceed 0.6 pound per million Btu gross heat content.