The Green Hill Fire Station reopened last week, free of mold and with a fresh coat of paint, according to Fire Chief Robert Hollingshead. The station had been closed since Nov. 14, when firefighters complained about a black substance in the building, which they worried was mold. Hollingshead said tests found a “very minor’’ amount of mold, which was removed by an environmental cleaning company. He said the station also was painted before it reopened on Dec. 17 and the fire truck that had been housed there moved back from the Central Fire Station, 2.6 miles away. “We’re glad we can get back to providing the appropriate level of public safety,’’ Hollingshead said.