TACOMA, Wash. — A report to regulators on the statewide 911 outage in Washington says emergency calls failed because they were stuck in a processing center in Colorado.

In the report last week to the state Utilities and Transportation Commission, CenturyLink says an estimated 4,500 calls over six hours early on April 10 were stranded at the center in Englewood, Colo., operated by the database manager Intrado. It ran out of capacity to route the calls.

The News Tribune reports (http://bit.ly/1o3ANiQ ) the outage affected 127 dispatch centers in Washington until calls were re-routed.

A state 911 project manager, Andy Leneweaver, says the outage also affected six to eight call centers in North Carolina and about 11 in Minnesota.

Century Link and Intrado say changes have been made to prevent another such 911 outage.