As wildfires raged in California this summer, one fire department’s response was impeded by an unexpected problem: data throttling.

In documents filed this week as part of a legal challenge to the FCC’s net neutrality repeal, Santa Clara County Fire Marshal Anthony Bowden explains how Verizon slowed device speeds during the crisis, hindering firefighters’ response.

In the documents, flagged by Ars Technica, Bowden writes that the fire department had purchased an unlimited data plan from Verizon for a support unit’s connection, but the company started throttling speeds “to 1/200, or less” after the unit hit 25GB of use.

Bowden writes that the resulting throttling from Verizon “had a significant impact on our ability to provide emergency services,” as responders were unable to properly track and route firefighting resources. The company continued to slow data speeds even after being informed it was “actively impeding” responders’ ability to fight the blazes, Bowden writes. Ultimately, the fire department had to sign up for a new, more expensive plan before speeds were restored.

The throttling took place after the repeal of net neutrality rules went into effect, although Verizon, like other major carriers, throttled unlimited plans at certain use thresholds long before that. The fire district, which filed the documents with 22 state attorneys general, did not argue that the company’s actions would have violated the previous net neutrality rules. Verizon did not immediately respond to a request for comment.

The filing includes an increasingly frantic email exchange between Verizon representatives and the fire department. A fire official expressed confusion over “why our public safety data usage is getting throttled down” when they were under the impression that would never happen.

“Please work with us,” a fire official wrote to Verizon at one point. “All we need is a plan that does not offer throttling or caps of any kind.”

Update August 21st 7:00PM ET: Verizon provided a statement to The Verge by email, acknowledging that it made an error in handling the Santa Clara County situation. The company says it should have lifted the reduced data speeds once alerted that the customer was dealing with an emergency situation, but that didn't happen:

This situation has nothing to do with net neutrality or the current proceeding in court. 

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.