Standard&Poor's Ratings Services affirmed its 'A-' rating on West Contra Costa Unified School District, Calif.'s outstanding general obligation bonds, reflecting: Fiscal oversight by state trustee and adequate financial performance and recovery from financial mismanagement in the early 1990s; Steady tax base growth; and Manageable, but growing, debt burden. These positive factors are offset by: Ongoing capital needs with slow amortization of outstanding debt; and Limited financial flexibility, somewhat constrained by union contracts that restrict further growth in average class size at most grade levels, and also grant health care benefits to retired employees. The more than 100 square-mile district is located 15 miles northeast of San Francisco, Calif. in western Contra Costa County, Calif. The district serves an