ALBANY — The company hired to process 1.8 million paper tax returns for the state botched the job so badly that state employees had to be rushed in at a cost of $6 million in overtime, an audit has found.

State Comptroller Tom DiNapoli said Dallas-based SourceHOV took about a month to process 90 percent of the paper returns filed last year — four times the expected time frame.

The audit also found that in 22 percent of the cases, employees the company supervised entered incorrect Social Security numbers and withholding amounts, and got wage and salary information wrong.

“The contractor hired by the state Department of Tax and Finance failed to meet many of its contract requirements and things quickly spun out of control,” DiNapoli said.

The department hired the New York State Industries for the Disabled, which in turn sub-contracted with SourceHOV to handled the 2013 returns. Under the contract, the vendor is responsible for the overtime tab. Several calls to SourceHOV were not returned.