A potentially lifesaving emergency alert system that Sonoma County officials decided against using during the deadly fires that swept through the area last month will finally get a long-planned upgrade, after nearly a yearlong delay by the Trump administration.

All wireless carriers will be required to more specifically target the areas where cell phones would receive Wireless Emergency Alerts, or WEAs. Sonoma County officials said they did not send such an alert as the fires raged late on the night of Oct. 8 because it would have hit phones all across the county, possibly causing panic and traffic jams that would have blocked people from getting in and out of the area.

They are among a number of local emergency officials who have found fault with the WEA system since it was put in place in 2012, including some who have declined to adopt it at all. Only about a third of all counties in the U.S. have access to the alert system, which is administered by the Federal Emergency Management Agency.

This past week, the Federal Communications Commission issued a rule requiring the nation’s big five wireless carriers to implement upgrades to the Amber Alert-style warnings that the agency had first ordered in September of 2016 but had been stalled due to industry objections.

The action followed a series of disasters, including three hurricanes that ravaged Texas, Florida and Puerto Rico, and the Wine Country fires, in which 43 people died, more than half of them in Sonoma County.

After The Chronicle reported on Sonoma’s decision not to send a wireless alert, Democratic Sens. Dianne Feinstein and Kamala Harris of California wrote to the FCC to complain about the delay.

Months earlier, long before Hurricane Harvey unleashed devastating floods on Houston, county officials there had pleaded with the FCC to upgrade the system, warning that more precise targeting was vital to assisting evacuation in a hurricane.

“It’s amazing that it took four disasters to make this come about,” said retired Adm. David Simpson, who was chief of the FCC’s Public Safety and Homeland Security Bureau during the Obama administration, which developed the new rule. “It should be an embarrassment to the commission, but it’s done.”

Even as the new rule takes effect, though, wireless carriers say many local officials do not understand or properly use the existing alert system. Emergency responders, meanwhile, are pushing for more improvements, in particular using phones’ geo-location technology to target WEAs even more precisely.

As currently programmed, Wireless Emergency Alerts — text-like messages accompanied by a unique loud sound and vibration — can be sent to most cell phones in an area during potentially life-threatening emergencies by pinging nearby cell towers. Every phone targeted by the alert receives it unless its user has opted to block it.

The main problem: By covering such large areas, the alerts can warn the wrong people to do the wrong thing, or possibly induce “alert fatigue,” leading some to ignore what might be a lifesaving warning.

Public safety officials said the revised system should allow targeting within a tenth of a mile.

The maximum length of a WEA text will increase from 90 to 360 characters, and can include links and phone numbers to direct people to more information. Also, a new class of “public safety messages” can convey recommended actions, such as boiling water or going to a shelter. And carriers must support transmission of the alerts in Spanish.

Some public safety officials, though, want further refinements that would take advantage of geo-location technology, which phone users already use daily to determine exactly where they are. Such a system would allow emergency managers to target each cell phone in only a designated emergency area. That would eliminate the potential for alerting too many or too few people.

But wireless service providers and device makers are putting up stiff resistance.

After President Trump was elected, promising to reduce government regulations, the trade association CTIA, which represents large wireless carriers such as Verizon and AT&T, effectively blocked implementation of the September 2016 upgrades, arguing that incorporating embedded links and phone numbers in alerts would congest networks.

“The election happened, and a very powerful lobby asked that this not be made a priority,” said Simpson, the former FCC public safety director.

Only last week did the FCC decide that the industry’s objections had no merit.

Justin Cole, spokesman for CTIA, said the industry works closely with public safety officials and government agencies “to maximize the proven lifesaving benefits of Wireless Emergency Alerts” and “has made additional enhancements to the alert system, including embedded references and geo-targeting below the county level, so even more lives can be saved.”

Sonoma County officials who made the decision not to send a mass alert on the night the Wine Country fires began said they decided to focus instead on notifying and evacuating specific areas. They turned to other cell phone alert systems that county residents must sign up for, which could reach only a small portion of the population, and used a “reverse 911” system to call landline phones in unincorporated areas. First responders also went door to door warning people in danger.

“There are half a million residents in the county, and that doesn’t include tourists,” said Zachary Hamill, emergency coordinator for Sonoma County Fire and Emergency Services. “We were really trying to focus on areas that were going to be impacted, because a lot of these areas are fairly rural and there’s one-way-in, one-way-out type situations.”

Many Sonoma County fire victims were incensed by the county’s decision not to send a wireless alert on the night of the fires. Lisa Tieber Nielson, whose Santa Rosa home was destroyed, said it could have prevented deaths.

“If they sent out an alert at 10 o’clock, saying there’s a fire, it’s in your area, get ready to leave at a moment’s notice, that would have saved a lot of people,” Tieber Nielson said.

She, her husband Dan and their two children fled only after receiving a warning call on their landline phone. Flames and explosions were already encroaching on their Larkfield-Wikiup neighborhood.

As they rushed out, Tieber Nielson thought about warning her elderly neighbor, but said there wasn’t enough time.

“It’s unspeakable the way I feel about not being able to do what I needed to do to help him out,” she said, adding she believes he was able to escape. “I don’t see why they couldn’t have just given us an advisory so we could have been prepared. There’s no excuse for that.”

Napa and Yuba counties, which were also hit by the recent wildfires, are among the roughly two-thirds of U.S. counties that do not use Wireless Emergency Alerts. Officials in both counties said imprecise geo-targeting has played a role in their decisions not to obtain the tool.

Lake County sent a wireless alert Oct. 9 issuing mandatory evacuations shortly after the Sulphur Fire broke out. Lt. Rich Ward, a spokesman for the Lake County Sheriff’s Office, said they were “battle tested” by the 2015 Valley Fire.

“There were lessons learned about getting the message out quickly and how to do that most efficiently,” Ward said. “With our limited personnel, trying to go door to door to get out the message just wasn’t enough.”

Officials in Riverside and Orange counties also sent wireless alerts to warn residents about fires this year. In both cases, it was the first time the counties had directly used the tool.

In Texas, Francisco Sanchez Jr., an official with Harris County’s Homeland Security and Emergency Management office, said the county, which includes Houston, used the wireless alert system only once during Hurricane Harvey, to ask people not to overload 911 emergency lines with calls unless a life was in danger.

Sanchez, who helped lead a major study of WEAs for the FCC, said being able to target alerts to a specific area “is perhaps the single greatest improvement that the FCC and carriers can make.”

Sanchez said that while the new FCC requirements allow more precise targeting of alerts than before, it remains only a “best approximation” of the area that needs to be notified. It involves emergency managers drawing a line around the area they want to alert, and cell service providers using that as a guide to decide which cell phone towers to “light up” to send the message.

Sanchez is urging the FCC to adopt new rules that would employ geo-location technology, taking advantage of the capacity of modern smartphones to pinpoint a person’s location within a few feet and decide whether the owner is within the emergency area or not.

“That’s already on the phone,” Sanchez said. “You use it to order pizza, you use it to drive, you use it to do all kinds of stuff.”

Last week, the National Academy of Sciences published a report recommending that emergency alerts take advantage of evolving cell phone technologies like geo-location, saying phone users now expect such a system.

Wireless providers say it’s one thing for a few people in a given area to order a car-share, another for everyone’s phone in the area to suddenly demand location information for a Wireless Emergency Alert.

Device maker Apple warned the FCC last August against such a plan, saying using phone locations to target WEAs would increase battery drain when power is most needed, as well as create “consumer privacy issues.”

Apple declined to comment for this story. But Sanchez said if Apple has privacy concerns, “perhaps they ought to prioritize public safety as much as they do making money off of geo-locating for all these apps that they make an incredible amount of money on.”

On Friday, FCC chairman Ajit Pai wrote to Sen. Harris saying he intends to propose further WEA upgrades “in the near future.”

He said that despite industry objections about the technical feasibility of using precise geo-location in the alerts, “based on our staff’s review of the record, we believe that it is possible to make additional progress on this issue.”

Pai also told Harris that the FCC has contacted all the California counties affected by the recent fires, as well as the state Office of Emergency Services. He said he was “concerned” by Sonoma County’s decision not to issue a wireless alert, and that the FCC will work with officials there to help them use the system more effectively, and follow up with the other counties as well.

Industry officials said it’s up to local emergency managers to generate wireless emergency alerts and understand how the system works, noting its low level of usage among counties. Even industry critics such as Simpson acknowledge that local emergency managers need to upgrade their systems and better train people on how to use them.

The new system allowing embedded links and longer alerts will be installed on most phones through software updates as soon as the rule is published in the Federal Register, which is expected to occur within a few weeks, officials said. Smaller carriers will have until May of 2019 to comply.

Meanwhile, some Sonoma County officials have pledged to review the decision not to send a wireless alert during the deadly fires.

Elizabeth Hawkins, whose home in Santa Rosa’s Riebli-Wallace neighborhood was destroyed, hopes the disaster will strengthen the county’s emergency response system.

Hawkins smelled smoke on the night of Oct. 8, but assumed she was not in danger because she heard no sirens and received no official warning.

“The system failed, the county failed, the city failed,” Hawkins said. “And we need to know as we rebuild that they will learn from their mistakes and improve things.”

Carolyn Lochhead is The San Francisco Chronicle’s Washington correspondent, and Joaquin Palomino is The Chronicle’s data and investigative reporter. Email: clochhead@sfchronicle.com jpalomino@sfchronicle.com Twitter: @carolynlochhead, @JoaquinPalomino