Three years after it shuttered its Calais field office, the Maine Department of Health and Human Services opened a new office there Tuesday, re-establishing a permanent presence in the eastern reaches of Washington County. First announced in June, the new office at 338 North St. will offer services that include processing of applications and renewals for public assistance programs. The state has signed a 20-year lease for the 3,500-square-foot building, according to Maine DHHS spokesperson Jackie Farwell.