Internet outages affected customers across the country Thursday.
The Monroe, Louisiana-based telecommunications company did not immediately respond to a request for comment on the FCC investigation or provide information as to how many customers were affected.
As of 3:30 Friday morning, CenturyLink tweeted that it was still working to restore service.
Mass. State police operate three regional PSAPs and a fourth is staffed by State 911 at the state police headquarters in Framingham.
Residents of the communities in the following lists can use the 10-digit phone numbers at the top of each list to receive dispatch service from State Police, according to MEMA.
King County spokesman Cameron Satterfield said systems appear to be working again, but they're still being tested to make sure everything is fixed.
The outage also did not affect text-to-911 in all areas where that feature is available.
In Idaho, the internet problems caused the temporary shutdown of phone services at the Idaho Department of Correction and the state's Department of Education, The Idaho Statesman reported. Patient records have been hard to access for medical centres in north Colorado and for other locations that haven't been confirmed.
In North Texas, Collin, Erath, Ellis, Hood, Hunt, Johnson, Kaufman, Navarro, Palo Pinto, Parker, Rockwall, Somervell and Wise counites faced 911 outages. Rather than using digital devices, they had to take notes with pencil and paper, according to the Greeley Tribune.
CenturyLink's status page notes the issue, caused by a "network element" problem, started at around noon Eastern Time on Thursday. Verizon said CenturyLink helps handle wireless network data traffic for Verizon and other wireless providers.