Lindsey Hoshaw, who lives near Treat and 24th Street, woke up in the early morning of March 11 to the sound of a woman screaming for help. She called 911. A recording told her to wait for a call taker. She did, for what she estimates was 30 seconds.

Frustrated, Hoshaw hung up and ran outside. To her relief, she found some other neighbors and learned others had already called 911. In five minutes or so, fire trucks arrived on the scene of the fire at 24th and Treat where two adults and three children from the Shaibi family lived. All were taken to the hospital, and within a week father Mohamed Shaibi and his 13-year-old daughter Amal died.

Though it’s not clear that a 911 delay played a role in the deaths, it still haunts Hoshaw and others. There have been at least four fires in the Mission District since the beginning of the year and they have caused three fatalities.

San Francisco’s average wait time last year was 7.7 seconds, within the 10-second goal set by national standards. In late 2014, when complaints about 911 delays were at their worst due to low staffing levels, a dispatcher reported 30 to 40 second wait times.

That’s better than in many cities. In Madison thousands of callers waited more than 40 seconds before a dispatcher became available. In San Diego, wait times of a few minutes are commonplace. In Minneapolis, callers experienced wait times as long as six minutes, eight according to some reports.

Nonetheless, another neighbor who called 911 for the fire on Treat and 24th Streets, Cynthia Wigginton, had the same experience as Hoshaw – twice. A few weeks after the Treat and 24th Street  fire, during which she also waited at length for her call to be answered, Wigginton heard gunshots on the street near her home.

She rolled out of bed, called 911, and waited for a dispatcher for what she estimates was 30 seconds, maybe even just under minute.

“If someone’s in immediate danger, that would be the end, you know. If they’re being physically threatened that could be the end,” Wigginton said. “That was another indication to me that the 911 system is overloaded.”

Emergency call volume has been increasing rapidly both in San Francisco and around the nation, and the city’s Department of Emergency Management is doing its best to hire dispatchers and figure out what’s causing the influx of calls so it can avoid leaving callers waiting.

The goal, prescribed by national standards, is to answer 90% of calls within ten seconds. In San Francisco, that percentage hovers in the high 80s, according to the Department of Emergency Management’s Deputy Director Robert Smuts. He has been at his post for about a year, and when Wigginton complained about her wait time, it was the first complaint he received from the public. But he knows call volume has been rising.

“Just diving in to the data, it was really striking how fast call volume was increasing,” Smuts said.

It’s a new development in a familiar problem. San Franciscans have been complaining about being put “on hold” by 911 for years. For a time, the emergency services struggled with sparse funds and understaffing, but since then Smuts said the mayor and City Hall have allocated the resources to bring staffing back up. Currently, between six and 13 call takers are ready to pick up the phone at a time, depending on expected call volume. The most call takers available used to be 11, and call takers have been picking up overtime shifts to meet current numbers.

Smuts said the emergency management is pushing hard to train and hire new dispatchers so more people are available to answer the stream of calls. With staffing increases, the goal is to maintain the new levels using only regular-shift staff and maybe add one more call taker during peak hours. If he can, Smuts would like to be able to get non-emergency calls answered faster, too.

But it takes nine months to train a dispatcher, and before they’re hired, they have to go through as extensive a background check as any new police officer – chats with previous employers, relatives, and friends are par for the course, since new call takers will regularly have access to sensitive police and medical information.

In an ideal world, call takers would always immediately pick up the phone, but Smuts described that as “pretty close to impossible,” which is why national standards don’t require it.

The call center processes about 1.2 million calls a year, a little over half of which are emergency calls to 911, and the rest of which are calls to the non-emergency line. San Francisco has what’s called a unified Public Safety Answering or Access Point, which means calls from both cell phones and landlines are routed to the same local center.

Technically, nobody is put on hold when they call 911 – the message to stay on the line is essentially the dispatch center’s ringback tone, the sound you hear instead of ringing.

Smuts acknowledged a distressed person in an emergency probably doesn’t care if it’s a ringback tone or they’re on hold, they want to talk to someone immediately. But it is an important distinction – a call taker will never break off the conversation with a caller to go do something else if their situation hasn’t been dealt with. And, like Hoshaw experienced, they’ll call back any number that hung up to make sure the emergency is being addressed.

As for the rising call volume, that’s a little more of a mystery. It’s possible that more calls are coming in because of the city’s population growth. It’s also possible that the infamous “pocket dial” has proliferated dramatically in the age of touchscreen, rather than flip, phones. Or that a shortage of emergency personnel is causing longer wait times for them to arrive, prompting frustrated citizens to call multiple times for the same emergency.

Whatever the cause, the emergency management team is going to get to the bottom of it. Google has donated 1,000 work-hours of a team of data analysts’ time to comb through the 911 call data available and figure out what really is responsible for the increase in call volume.

The three young number crunchers began work on the project a few weeks ago. They seemed happy to assist.

“This project had lots of interest,” said James Driscoll, who usually works in privacy engineering. “The city could probably run it on their own, but they’re busy running the department!”

As the analysts sifted through call data upstairs, dispatcher hopefuls filled a classroom downstairs, waiting to join the once-depleted ranks of call takers and face the flood of emergency calls – hopefully, without having to put anyone on hold.