Comcast’s Xfinity phone service is apparently suffering a massive outage today, knocking out phone service for thousands of companies across the country that still largely rely on landline access to do business. According to DownDetector.com, Comcast phone service began experiencing issues around 8AM ET this morning and by the afternoon, areas around the country have started reporting disruptions. The areas most affected appear to be the Pacific Northwest, California, the tri-state area, and Florida.

The official support Twitter account for Comcast Xfinity’s residential and business services has acknowledged the issues, tweeting at 1PM ET today that some “customers may still be experiencing an issue with their Voice service,” though Comcast has yet to release an official statement regarding the issue.

@comcastbusiness customers may still be experiencing an issue with their Voice service. We appreciate your patience as we continue to resolve. Please continue to check back here for more updates. — ComcastCares (@comcastcares) June 6, 2018

A cursory search on Twitter shows hundreds of users complaining about the business phone outage and the effect it’s having, and many companies seem to be attempting to route calls through cell phones or alternative methods.

Comcast is having issues since 11:28 AM ESThttps://t.co/he0RZm1TIj

RT if you're also affected #comcastoutage pic.twitter.com/1yWrkCKKb9 — Outage Report (@ReportOutage) June 6, 2018

Due to a Comcast phone service outage in our area, our phone service is down until 4:00! (6/6/18) We are working on routing incoming calls to a cellphone and will update you promptly. Please email an administrator if you need assistance. pic.twitter.com/FiH5s4U6hz — Glen Montessori (@GlenMontessori) June 6, 2018

Others, like radio host Thom Hartmann, pointed out how Comcast’s stranglehold on the landline market makes US companies especially susceptible to situations like this, where one provider can cripple large swaths of a country.

The #comcastoutage shows the danger of giant monopolies. In Europe, you can get your phone and internet service from any company you want (over 100 in France!), regardless of who owns the copper or fiber coming into your home or business. Here, we get monopoly and screwed. — Thom Hartmann (@Thom_Hartmann) June 6, 2018

In at least one case, granted a very troubling one, the outage affected landline 911 calls to Washington’s Spokane County police department, with the Greater Spokane Emergency Management department informing residents to use their cellphone in an emergency to contact law enforcement.

We have been informed that there is a Comcast phone outage in Spokane County. You may not be able to reach 911 with your landline (VOIP) phone and should use your cell phone if you need to call 911. — Greater Spokane EM (@GEGEmergencyMgt) June 6, 2018

The issue was later resolved for Spokane County, but it’s clear a Comcast landline outage is a serious matter that could affect police and ambulance response.

In a statement issued around 3:30PM ET, Comcast says service has been restored for most of its customers. “We experienced a service interruption today with our Comcast Business Voice and VoiceEdge Select services and we apologize,” a company spokesperson said. “Our engineers began working to address the issue immediately and services have been restored for most of our customers. We recognize that some customers are still impacted and we expect the issue to be fully resolved shortly. We have every resource focused on getting everyone back online and apologize again to the customers who were affected.”

Update 6/6, 3:30PM ET: Added statement from Comcast.

Correction: Spokane County is located in Washington, not Oregon. We regret the error.