The state of West Virginia will not repeat accounting mistakes made under a former chief financial officer, said Health and Human Resources Secretary Gretchen Lewis.
Robert High left the department late last month, shortly after errors left a $100 million deficit in the state's Medicaid program.
Ms. Lewis refused to give a reason for his departure.
Ms. Lewis, who was appointed secretary in January, said the Medicaid estimates were put together manually and not double-checked.
Because of the errors, an anticipated $8 million Medicaid surplus became a deficit that forced the agency to take $39 million from a special trust fund in June.
The mistake was "a pretty incredible error," she said.
Officials say the problem was partly caused by the federal government's disallowance of more than $25 million for services to foster children.
A replacement for Mr. High has not been named.
Medicaid is the state-managed health insurance program for the poor.
Mr. High could not be reached for comment.