California firefighters’ ability to battle a huge wildfire was impeded by Verizon Wireless throttling their internet connection, in a moment advocates say demonstrates the high stakes of the battle over net neutrality.

Santa Clara county fire department had paid for what Verizon described as an “unlimited” data plan for various internet-connected devices, but the data flow was throttled to about 1/200th of the typical speed – unusably slow for any meaningful data transfer.

This restriction created problems for a command and control communications vehicle called OES 5262 as firefighters battled the Mendocino Complex fire, the largest wildfire in California’s history, in late July. The vehicle – essentially a fire engine that is fitted with computers and communications equipment – gets internet access via a device that uses a Verizon sim card. It is used as a hub to “track, organize and prioritize routing of resources around the state and country to the sites where they are needed the most”, according to the Santa Clara county fire chief, Anthony Bowden, in a lawsuit over net neutrality protections, first reported by Ars Technica.

“This throttling has had a significant impact on our ability to provide emergency services,” said Bowden. “Verizon imposed these limitations despite being informed that throttling was actively impeding County Fire’s ability to provide crisis-response and essential emergency services.”

Obama-era protections would have given the fire department the recourse to bring a complaint to the FCC, which could have taken action against Verizon.

The July incident wasn’t the first time Verizon had throttled the firefighters’ data connection.

They had previously contacted Verizon in June when they were dealing with the Pawnee fire and December 2017 when they were battling a grass fire near Prado regional park.

According to emails included in court filings, in June 2018, the fire captain Justin Stockman contacted Verizon requesting that the data connection for a critical piece of communications equipment was unthrottled. A Verizon account manager responded by trying to upsell the fire department from a $37.99 plan to a $39.99 plan.

“In light of our experience, County Fire believes it is likely that Verizon will continue to use the exigent nature of public safety emergencies and catastrophic events to coerce public agencies into higher-cost plans, ultimately paying significantly more for mission-critical service – even if that means risking harm to public safety during negotiations,” Bowden wrote in a written declaration.

Internet service providers (ISPs) are entitled to throttle people who use excessive amounts of data, depending on the terms of the individual plan. However, Verizon has a policy to remove restrictions if contacted in an emergency situations.

“We have done that many times, including for emergency personnel responding to these tragic fires. In this situation, we should have lifted the speed restriction when our customer reached out to us. This was a customer support mistake,” said the company in a statement published on Tuesday.

Harold Feld, from Public Knowledge, one of the organisations bringing the suit, said: “Companies need to be liable for their actions,” adding: “Verizon’s response of ‘I’m terribly sorry your state is burning down, let me sell you this new package’ is not good enough. We need rules to prevent it from happening in the first place.”

The Santa Clara fire department’s complaint forms part of a large lawsuit against the Federal Communications Commission seeking to overturn the repeal of net neutrality rules that prevent internet service providers from blocking, throttling and paid prioritisation.

The Obama-era protections had widespread public support but were scrapped last year by Trump’s Federal Communications Commission, with the former Verizon lawyer Ajit Pai at the helm. At the time, Pai argued that ISPs should self-regulate instead as government regulation would stifle innovation in the industry. He also said that the net neutrality rules were established on “hypothetical harms and hysterical prophecies of doom”.

“This should be a warning to lawmakers of what happens when there aren’t protections in place,” said Mark Stanley from digital rights group Demand Progress. “ISPs simply can’t be trusted to police themselves.”

“If Verizon was willing to do this to a fire department during the state’s largest wildfire, when public safety should have been paramount, it’s easy to imagine what they are willing to do to everyday consumers,” he added.