Throttling of its Internet speeds per a lower-priced Verizon data plan had a significant impact on one fire department's ability to provide emergency and potentially life-saving services.

That is according to testimony and documents provided by the fire chief of Santa Clara County, one of the California counties fighting the largest wildfire in the state's history. It came in the legal challenge to the FCC's lifting of regulations against online blocking, throttling and paid prioritization.

Related: Court Sets Briefing Schedule for Net Neutrality Challenge

Initial petitioners' briefs to the U.S. Court of Appeals were due Aug. 20, and in an addendum to one of those, fire chief Anthony Bowden said that county fire personnel had to use other agencies ISPs and their own personal devices and that while Verizon did ultimately lift the throttling, it was only after the fire department had subscribed to a new, more expensive, plan.

That came after, in the midst of responding to the Mendocino Complex Fire, they found that their data rates had been reduced to 1/200th or less of previous speeds, meaning it was essentially nonfunctional, "despite being informed that throttling was actively impeding County Fire's ability to provide crisis-response and essential emergency services," he told the court, adding: "Even small delays in response translate into devastating effects, including loss of property, and, in some cases, loss of life."

Verizon responded that it usually lifts such limits when contacted by emergency services, and should have done so in this case.

Bowden included copies of an email string from July that contained the following from someone identified as a Verizon government accounts manager:

"All unlimited data plans offered by Verizon have some sort of data throttling built-in, including the $39.99 plan. Verizon does offer plans with no data throughput limitations; these plans require that the customer pay by the GB for use beyond a certain set allotment."

"[P]ublic safety customers have access to plans that do not have data throughput limitations. However, the current plan set for all of SCCFD's lines does have data throttling limitations. We will need to talk about making some plan changes to all lines or a selection of lines to address the data throttling limitation of the current plan."

"This situation has nothing to do with net neutrality or the current proceeding in court," Verizon said in a statement.

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