Santa Clara County Fire Chief Anthony Bowden made the claim in an addendum to a brief that 22 state attorneys general filed in a lawsuit seeking to overturn the Federal Communications Commission’s repeal of net neutrality rules. The declaration was first reported by tech news site Ars Technica.

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

According to Bowden, a department vehicle uses for command and control in large fires was deployed to the Mendocino wildfire, where data throttling “severely interfered” with its ability to function effectively.

The county’s fire department had paid Verizon for “unlimited” data but saw its wireless-data speeds slowed to 1/200th of its usual speeds. The throttling stopped once Santa Clara agreed to pay Verizon more money, the declaration said.

“Verizon representatives confirmed the throttling, but rather than restoring us to an essential data transfer speed, they indicated that County Fire would have to switch to a new data plan at more than twice the cost, and they would only remove throttling after we contacted the Department that handles billing and switched to the new data plan,” Bowden wrote.

Verizon responded to the declaration by saying it “has nothing to do with net neutrality.” The Santa Clara fire department signed up for a plan that give unlimited data, although the speed of that data will slow once a certain allotment is reached, said Verizon spokeswoman Heidi Flato in a statement. But, she said, Verizon “made a mistake” in its communications with the fire department.

“Regardless of the plan emergency responders choose, we have a practice to remove data speed restrictions when contacted in emergency situations,” Flato said. “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.”

The result was the Santa Clara fire department had to rely on the personal devices of its workers or the ISPs used by other fire departments. The throttling in Mendocino wasn’t the first such incident, and Bowden said that Verizon will likely keep restricting data during emergencies to force public agencies into more expensive plans.

“The Internet has become an essential tool in providing fire and emergency response, particularly for events like large fires which require the rapid deployment and organization of thousands of personnel and hundreds of fire engines, aircraft, and bulldozers,” Bowden said in the declaration.

Net neutrality is the principle that all Internet traffic should be treated equally and not subject to “fast lanes” for customers willing to pay extra. Before the FCC repealed net-neutrality rules in February, the agency heard complaints from people and entities who believed their data was being unreasonably throttled.

This story has been updated to add a response from Verizon.