The Minnesota Office of Pipeline Safety is investigating CenturyLink over hundreds of complaints that the utility failed to respond to requests to locate underground cabling.

CenturyLink faces more than $780,000 in fines for its alleged violations of a law intended to protect the safety people and utility infrastructure, according to a state Office of Administrative Hearings document.

The Louisiana-based utility sells internet, TV and phone services in Minnesota.

In Minnesota, Gopher State One Call manages requests to dig underground.

State law requires homeowners, farmers and professional contractors to notify the office before digging. Utilities like CenturyLink must respond to the request, often by marking the location of underground infrastructure on the surface.

The Legislature established the office after a liquid pipeline erupted in flames in Mounds View, Minn., killing two people.

In the current case, CenturyLink allegedly didn’t respond to hundreds of requests beginning in April.

CenturyLink said in a statement it changed its contractors for locating requests in April, and the new contractor had “unanticipated staffing issues.” The utility said it is coordinating with its contractor and the state to catch up on the backlog of locate jobs.

“We apologize for these delays and appreciate your patience as we work to get this situation resolved,” CenturyLink’s statement said.