Verizon has been accused of throttling the data plan of a California fire department in the midst of the state's worst-ever wildfire.

Chief Anthony Bowden of the Santa Clara County Central Fire Protection District says that [PDF] while his department's Incident Support Unit (OES 5262) was working to coordinate efforts to fight the massive Mendocino Complex Fire, Verizon slowed their "unlimited" data plan to a trickle, potentially putting public safety at risk.

The firefighters' 4G monthly service plan slows down connections after the first 25GB has been downloaded within a month, although they were under the impression this speed restriction was not in place due to being a public emergency service. Late last year Verizon temporarily lifted this restriction for the firefighters, however, it was back in place by the June wildfires – which the crew did not expect.

"In the midst of our response to the Mendocino Complex Fire, County Fire discovered the data connection for OES 5262 was being throttled by Verizon, and data rates had been reduced to 1/200, or less, than the previous speeds," Bowden said in his statement.

"These reduced speeds severely interfered with the OES 5262's ability to function effectively."

What's worse, Bowden says, even after his department contacted Verizon and appraised them of the situation, the telco admitted to throttling the connection, and wouldn't restore the emergency service's bandwidth unless they agreed to purchase an upgraded service plan.

After having to rely on the ISPs of other departments for data transmissions and communications, Bowden said Verizon did eventually restore Santa Clara County Fire's service – at double the cost.

"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.

Verizon promises to stop selling its subscribers' location data... for now READ MORE

Bowden's letter was filed as part of the supporting evidence to back the ongoing challenge Mozilla has made to the FCC's recent decision to revoke net neutrality protections in the US.

Verizon said in a statement to The Register that the issue had nothing to do with the net neutrality case, and was a customer service mix-up.

"We made a mistake in how we communicated with our customer about the terms of its plan," Verizon told us.

"Like all customers, fire departments choose service plans that are best for them. This customer purchased a government contract plan for a high-speed wireless data allotment at a set monthly cost. Under this plan, users get an unlimited amount of data but speeds are reduced when they exceed their allotment until the next billing cycle.

"Regardless of the plan emergency responders choose, we have a practice to remove data speed restrictions when contacted in 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. We are reviewing the situation and will fix any issues going forward." ®