Widespread 911 outages are reported in four states

A large-scale outage on Wednesday affected residents’ ability to call the 911 emergency number in parts of Nebraska and Texas, the entire state of South Dakota and Las Vegas, according to local authorities.

In portions of Nevada, South Dakota and Nebraska, an outage was caused by a “third party company” that was installing a light pole, Lumen Technologies, a telecommunications company, said in an emailed statement Thursday.

Lumen did not say where the third-party company had installed the light pole. Lumen does not provide 911 services in Texas, a spokesperson said.

The Federal Communications Commission said in a post on social media that the 911 outages were under investigation.

In Las Vegas, calls to 911 on landline phones and mobile phones were not connecting for about two hours before service was restored at about 9 p.m., the Las Vegas Metropolitan Police Department said on social media.

During the outage, dispatchers could see attempts to make calls from mobile phones and would call residents back, police said, and all attempted calls had been answered.

The outage also affected southern Nevada, the Nevada State Police said.

Outages were also reported by the local police departments of Dundy, Kearney and Howard in Nebraska. All three said between 12 a.m. and 12:30 a.m. on Facebook that service had been restored. In Chase County, local authorities said the line was down across the state for all cellular carriers except T-Mobile, but landlines could still call through.

The police department of Del Rio, Texas, said customers of one cellular provider were having issues calling 911. A spokesperson said the issue there was only affecting T-Mobile customers, and that service had not yet been restored to those customers at 1:15 a.m.

The South Dakota Department of Public Safety said on social media that the outage was affecting residents throughout the entire state. In most parts of the state, residents could still text 911, and call their local police and county sheriff offices on their nonemergency phone lines, the department said. Among the areas affected were Sioux Falls and Rapid City, where officials provided alternate numbers before the line returned.

About 11 p.m., the South Dakota Highway Patrol said on social media that service had been restored.

At a news conference Thursday, officials in Sioux Falls said that 911 service was lost from 7:59 p.m. to 10:38 p.m. They said that the cause of the failure was unknown.

It was not immediately clear what had caused the outage. In February, a widespread AT&T outage temporarily cut off connections for users across the United States for many hours, leaving FirstNet, the emergency communications network, out of service. Police forces like the New York Police Department were unable to make calls or send emails.

This article originally appeared in The New York Times.