An oil spill that temporarily closed the Smith Canal to fishing is in the final throes of being cleaned up. The Coast Guard has turned over responsibility for the effort to the Environmental Protection Agency for ongoing monitoring.  “We go out and get (with) contractors and oversee their work and make sure it gets done properly,” said Michael Brogan, a San Francisco-based spokesman for the EPA.  Initial reports from the Coast Guard noted that a container with a capacity of 380 gallons had been discovered in the area, but that figure was later downsized to a 280-gallon capacity, Brogan said. While it is not clear how much oil was released, “this is a relatively small spill,” Brogan said, adding that it still needed to be treated quickly and seriously. … The spill, believed to have been caused by illegal dumping, was discovered Sept. 28 when a sheen was spotted on the water. About a mile of the canal from Yosemite Lake at American Legion Park to Mission Road was closed. Absorbent booms were deployed in an effort to contain the oil.