PITTSFIELD, Mass. — A lake that’s had garbage, sewage and PCBs dumped in it, that’s been the site of two major oil spills and that once caught fire is now considered clean enough for some recreational activities.

Workers capped major polychlorinated biphenyl contamination in Silver Lake’s bottom last fall, one of the last procedures in a 16-year effort to clean the 26-acre body of water and open it to catch-and-release fishing, boating and ice skating.

Pittsfield Mayor Daniel Bianchi remembers Silver Lake not freezing in winter and even changing colors at times.

“I think it’s absolutely wonderful to have a nice lake in the middle of the city,” Bianchi told The Berkshire Eagle.

Levels of PCBs are undetectable in the water, although the sunfish, carp and largemouth bass found in the lake have high levels of the suspected carcinogen and are not suitable to eat, said David Dickerson, the Environmental Protection Agency’s project manager for Silver Lake.

The remaining PCBs have been found only in sediment since the lake bottom was capped, Dickerson said. They do not pose a risk to swimming, but swimming is still “discouraged,” said Parks and Open Space Manager James McGrath.

The bottom of the lake is capped with a combination of sand and topsoil that was mixed with water to create a slurry, Dickerson said. The topsoil contains carbon, which he described as a “magnet” for attracting PCBs that enter the water. The mixture was then spread along the bottom through pipes hooked to a barge that moved back and forth.