Waymo and other robotaxi operators are facing increased scrutiny — and possible new federal requirements — over how their autonomous vehicles interact with emergency responders, a regulatory risk that’s becoming harder for the industry to shrug off.

Rep. Kevin Mullin (D-Calif.) is the latest lawmaker to put pressure on the industry with a proposed bill that would direct federal regulators to establish minimum national safety standards for autonomous vehicle operators. The proposed legislation, expected to be introduced in Congress this week, follows a number of incidents in which autonomous vehicles have blocked ambulances and fire trucks, driven into active crime scenes, and failed to recognize safety signals such as traffic cones and flares.

A TechCrunch investigation earlier this year identified a number of incidents in which Waymo relied on first responders to manually drive its vehicles when they encountered issues.

The legislation, called the AV Emergency Response Coordination Act, was unveiled Tuesday during a press conference in San Francisco, a hub of autonomous vehicle testing and where hundreds of Waymo robotaxis already give rides to paying customers. San Francisco Mayor Daniel Lurie, San Francisco Fire Chief Dean Crispen, and Advocates for Highway and Auto Safety President Cathy Chase also spoke at the press conference.