EVERETT — A Snohomish County Superior Court judge on Wednesday told a former drywall contractor in Marysville to be prepared to go to prison for a long time if he doesn’t start paying back more than $2.1 million he owes the state in unpaid sales tax and workers’ compensation.

Mark Standley admitted in October that he reported less than one-half of one percent of the sales tax he collected for his business, Master’s Touch Drywall, between 2003 and 2008. He also admitted that he failed to pay workers’ compensation premiums on employees he hired to do these jobs.

State officials said it could be one of the largest sales tax thefts on record.

Standley faces up to 9½ years in prison.

As part of the plea agreement, Standley’s sentence could depend on how much restitution he makes to the state Department of Revenue and the state Department of Labor and Industries.

Assistant Attorney General Scott Marlow said on Wednesday that Standley has failed to make any payments since his plea last fall. Marlow said state officials prefer to see Standley pay his debt to taxpayers, rather than send him to prison.

A judge gave Standley until Sept. 15 to make significant efforts to pay back the money. If he hasn’t, he should be prepared to be hauled off to prison, Judge Ellen Fair said.