40 C.F.R. § 52.1128
The City of Cambridge; that portion of the City of Boston from the Charles River and the Boston Inner Harbor on north and northeast of pier 4 on Northern Avenue; by the east side of pier 4 to B Street, B Street extension of B Street to B Street, B Street, Dorchester Avenue, and the Preble Street to Old Colony Avenue, then east to the water, then by the water's edge around Columbia Point on various courses generally easterly, southerly, and westerly to the center of the bridge on Morrissey Boulevard, on the east and southeast; then due west to Freeport Street, Freeport Street, Dorchester Avenue, Southeast Expressway, Southampton Street, Reading Street, Island Street, Chadwick Street, Carlow Street, Albany Street, Hunneman Street, Madison Street, Windsor Street, Cabot Street, Ruggles Street, Parker Street, Ward Street, Huntington Avenue, Brookline-Boston municipal boundary, Mountford Street to the Boston University Bridge on the southwest and west; and the Logan International Airport. Where a street or roadway forms a boundary the entire right-of-way of the street is within the freeze area as defined.
40 C.F.R. §52.1128