Australian telco Optus has been served an AU$12 million ($8m) fine for its triple zero outage last year.

The outage, which happened on November 8, 2023, lasted more than 14 hours and affected more than 10 million customers. Triple Zero (000) is Australia's main emergency service phone number.

Australia's Communications and Media Authority (ACMA) handed out the fine to Optus, which it notes has been paid by the carrier.

In a statement, ACMA said it found Optus had failed to provide access to the emergency call service for 2,145 people during the outage.

On top of this, Optus then failed to conduct 369 welfare checks on people who had tried to make an emergency call during the outage, added ACMA.

“Triple Zero availability is the most fundamental service telcos must provide to the public. When an emergency call fails to connect there can be devastating consequences for public health and safety,” said ACMA chair Nerida O’Loughlin.

The fallout from the outage was so severe for Optus, that its CEO at the time, Kelly Bayer, resigned, before its head of networks, Lambo Kanagaratnam, also quit months later.

Optus said that it has conducted a review of its systems and processes, to ensure it's better prepared to better manage emergency calls during network challenges.

The ACMA added that the outage has prompted it to make updates to the Telecommunications (Emergency Call Service) Determination 2019.

“Beyond the penalties announced today by the ACMA, the Optus outage has directly led to changes for industry regulatory obligations in relation to emergency call services,” O’Loughlin added.

“This will require further actions and investment by telcos, including Optus, to provide better safeguards for consumers and enhance the Triple Zero ecosystem so that Australians can have even greater confidence they will be able to get through to emergency services when they need it.”