T-Mobile failed to alert 911 call centers affected by the outages in a timely manner, the investigation found.

T-Mobile will pay $17.5 million for two 911 outages past year in a settlement with the Federal Communications Commission (FCC), the agency announced on Friday. The government agency also charged T-Mobile with being too slow to alert first-responders to the outages and didn’t have “appropriate safeguards” in place.

The settlement represents the largest fine that the FCC has assessed against a carrier in connection with a 911 outage.

Both outages were nationwide, preventing nearly all of T- Mobile’s then 50 million customers from reaching 911 operators for nearly three hours if they needed help.

T-Mobile is paying the largest 911-related fine against a wireless carrier to date.

“Communications providers that do not take necessary steps to ensure that Americans can call 911 will be held to account”, Wheeler said.

During that outage, emergency workers missed 6,600 calls to 911, reporting urgent situations including “domestic violence, assault, motor vehicle accidents, a heart attack, an overdose, and an intruder breaking into a residence”, the FCC said in its enforcement announcement. CenturyLink was required to pay $16 million, Verizon paid $3.4 million and Intrado Communications, an emergency equipment provider, paid $1.4 million.

T-Mobile released a statement saying that while the company has already improved its systems, it will continue to do so.

The compliance program in the settlement requires T-Mobile to develop new processes to identify risks that could result in disruptions to 911 services, detect future outages and take remedial actions, including prompt notifications to affected emergency call centers.

“We have made significant changes and improvements across a number of our systems since past year, and we will continue working to improve these critical systems with our partners to provide the standard of service our customers rightly expect from T-Mobile”, the company said in an e-mailed statement. You can read the full press release from the FCC in the source links down below.