To avoid conflicts, the FAA has issued temporary flight restrictions within 100 miles of Houston through Sept. 5 and within 30 miles of Rosenberg through Sept. 30.

“As we are using military assets to respond and recovery, and civilian assets to respond and recovery, the potential for drone impact is a big deal,” Air Force Maj. Gen. James Witham, director of domestic operations for the National Guard, said in a Pentagon briefing Tuesday. “As much as possible, if we could keep civilian drones out of the crowded skies that are already crowded with people doing response and recovery efforts, that would certainly be helpful because those present a hazard for our crews operating those helicopters in the region.”

The Academy of Model Aeronautics, a group representing nearly 200,000 hobbyists, urged drone pilots to steer clear of Harvey response efforts.

“The ongoing emergency response efforts are of the utmost importance,” Rich Hanson, the group’s president, said in a statement. “We urge everyone to be careful and avoid interference with any of these crucial operations.”

As Harvey approached, the FAA did what it usually does in emergencies: It restricted air space in the affected region. That means commercial and private aircraft, including professionally operated drones, are banned from the area until the government says otherwise. “Unauthorized drone operators may prevent the response and recovery aircraft from safely doing their jobs,” says Laura Brown, an FAA spokesperson.

But the FAA has found exceptions to its rule, issuing at least 43 unmanned aircraft system authorizations for groups involved in response and recovery efforts. These waivers let specially sanctioned operators fly in the otherwise verboten airspace, but operators still have to follow the basic regulations for small drones: flying below 400 feet and within the pilot’s line of sight, and not over large crowds of people.

Oil and gas companies have claimed five of those authorizations, which they’ve used to inspect their facilities, power lines, and fuel tanks. Union Pacific Railroad grabbed eight, and has had three certified operators flying DJI Mavic Pro drones in the area since Tuesday, inspecting flooded and hard-to-reach areas, like rail yards. Meanwhile, their operations team back at HQ inspects the conditions through a live feed. “This is especially useful for bridge examinations looking for track washouts and other structural changes,” says Raquel Espinoza, a Union Pacific spokesperson.

Pilots working for Fort Bend County, to the southwest of Houston, have used drones to assess damage to roads, bridges, and water treatment plants—and posted the footage online. Other local governments and agencies, including fire departments and state environmental quality officials, have worked with drone operators to identify flooding and drainage problems.

Parker Gyokeres, a New York-based drone pilot, arrived to volunteer in the Houston area on Sunday afternoon, as floodwaters rose. “We probably shouldn’t have done it—it was really stupid—but it was the right thing to do,” he says. He’s now part of an eight-person team of professional pilots and mappers who are working with local government agencies and the Red Cross to assess the damage and work out how to respond. (They have received special authorizations from the FAA for humanitarian operations, and will not be conducting commercial work in the area, Gyokeres says.)

On Friday, the group was lugging an RV and flat-bottom boat around Katy, Texas, to the west of Houston, where they’ll row out to the middle of flooded neighborhoods to run their missions. (“Texas is really big,” Gyokeres says.) Drones have an advantage over even helicopters in this response situation, he says, because they’re cheaper, can fly lower, and don’t risk pilots’ (and passengers’) lives as they move around in the sky.

Meanwhile, insurance companies are launching their own fleets of drones, in efforts to tally up and verify claims. Allstate will use hundreds of drones in its Harvey-related deployment, its largest since it began experimenting with drone assessments a few years ago, says Justin Herndon, a spokesperson for the insurance company. “We’re going to be there for a while.”

Allstate works with an aerial imagery company to coordinate its drone operations, which in turn contracts with freelancing drone pilots, each of whom maintain their own drone equipment. Those freelancers must not only pass their pilots’ exams but complete specialized training and ensure their drones are up to par. (The DJI Phantom 4 and Mavic Pro, about $800 and up, are both acceptable models.)

Drones are especially convenient for checking out insurance claims because they’re fast, nimble, and can carry excellent cameras. They can relay footage back to Allstate’s claim adjusters in real time, so they can get started on their work even before the drone pilot leaves the area. “You can zoom in at your desk to a single shingle and see the characteristics of that particular piece,” Herndon says.

Perhaps most impressive of all, unauthorized drone flyers haven’t seriously run afoul of the rules. Earlier this summer, firefighters battling a blaze in Prescott, Arizona, had to ground aircraft and pull out crews for an hour after a pilot spotted an unauthorized drone in the area. (Law enforcement charged a man with 14 counts of endangerment for the incident.) Authorities fighting fires in Montana have run into similar issues.

Not so in Houston: “We’ve had a few reports [of misbehavior] but nothing widespread,” the FAA says. Stay safe, Texas—and let the remote control pros handle the skies.