The US Federal Communication Commission (FCC) has opened a major public investigation after a data centre outage left several states unable to handle 911 calls – and telecommunications giant CenturyLink urging those affected to “drive to the nearest emergency facility instead”.

The CenturyLink outage began Thursday December 28 at 17.18 UK time.

CenturyLink, the US’s third largest telecommunications providers described the issue in an initial alert late Thursday as “an incident affecting the CA1, CA2, IL1, NY1, UC1, VA1, VA2 and WA1 data centers.” Some 12 hours later, it said its engineers had identified the fault as an unspecified “network element”.

centurylink outagePolice departments across the country tweeted and texted alerts to residents, announcing that 911 services were down and offering alternative numbers

CenturyLink Outage: 911 Call Centres Hit

By late Friday, for example, Seattle Police Department said its call centre was now receiving 911 calls, but offered an alternative number for those unable to get through.

More than 24 hours after the initial alert, some services were still not restored, the company’s status page showed.

Announcing an investigation, FCC Commissioner Ajit Pai descibed the CenturyLink service outage as “completely unacceptable”, adding that its “breadth and duration are particularly troubling.”

Just days earlier, CenturyLink, which primarily serves enterprise customers and which generated revenues of $5.82 billion in Q3, had advertised a “robust, resilient” disaster recovery solution in association with Microsoft Azure. (The latter’s infrastructure is not in any way associated with this outage. It is unclear when CenturyLink last tested its own disaster recovery plans).

CenturyLink provides internet and phone backbone services to major cell carriers, including AT&T and Verizon. It describes itself as a “Tier 1 ISP and international carrier offering multiprotocol label switching (MPLS), virtual private network (VPN), Ethernet virtual private line (EVPL), Ethernet private line (EPL) and private line services.”

The company offers over 350 carrier neutral data centres globally.

Over 24 hours after the initial outage which appears to have had nationwide consequences, it has yet to offer any further details on the cause of the outage.

See also: UK Police Adoption of Tech a “Complete Mess”