A battle over background checks for Uber drivers at the world’s busiest airport has developed, even as cities like Los Angeles and Austin, Texas consider more thorough screenings to prevent criminals getting behind the wheel.

The Atlanta airport has announced plans to use fingerprints to check the criminal records of Uber’s drivers, a move the ride-booking giant has contested, claiming that its own record checks are sufficient.

But the district attorney in Uber’s hometown of San Francisco has called Uber’s screening process “completely worthless,” since drivers aren’t fingerprinted.

In Houston, city officials say they have found that background checks without fingerprints allow criminals who have been charged with murder, sexual assault, and other crimes to evade detection in a variety of ways.

Atlanta’s city council on Wednesday is set to consider the airport’s plan for screening drivers for Uber, Lyft, and other ride-booking firms when proposed new rules go before the council’s transportation committee.

Uber has agreements with more than 50 U.S. airports, none of which require the fingerprint-based background checks being proposed by Atlanta’s airport, the company said in a statement. Those airports include major air hubs in Denver; Los Angeles; Memphis, Tennessee; Charlotte, North Carolina; and Salt Lake City, Utah.

But New York City fingerprints drivers, and the mayor of Los Angeles this month asked state regulators to allow his city to do so, as well.

Houston, the nation’s fourth-largest city, was among the first in the U.S. to require drivers for Uber and other ride-booking firms to undergo fingerprint-based background checks using the FBI’s database. Houston’s program began in November 2014, and city officials there say these fingerprint-based searches are far more thorough than any other way of checking criminal history.

Uber CEO Travis Kalanick speaks to students during an interaction at the Indian Institute of Technology (IIT) campus in Mumbai, India, January 19, 2016. REUTERS/Danish SiddiquiREUTERS/Tami Chappell

“Public safety is our No. 1 priority — that’s something the city of Houston does not compromise on,” said Lara Cottingham, Houston’s deputy assistant director of administration and regulatory affairs. “That’s the reason we license any vehicle for hire.”

Since Houston’s ordinance went into effect, the city’s fingerprint-based FBI background checks have found driver applicants who have been charged with murder, sexual assault, robbery, and indecent exposure, among other crimes. Those drivers had already cleared the commercial background checks used by ride-for-hire companies, according to a city report released this month.

Potential drivers can pass background checks that don’t rely on fingerprints simply by using an alias, the report found. For instance, one driver cleared by a company that does background checks for Uber underwent Houston’s fingerprint check, which turned up 24 alias names, 10 listed social security numbers, and an active arrest warrant, the report states.

Companies that perform background checks for ride-hailing firms typically seek to identify counties where applicants have lived in the past, then search public records from those places, the report states. But the checks don’t search every county, creating “a huge potential gap where crimes go undetected,” the report states.

“The FBI provides the only true nationwide check,” according to the report.

FBI James ComeyREUTERS/Tami Chappell

Uber has now been operating in Houston for more than a year, “and everything we’ve seen is that the number of drivers getting licenses continues to grow and their business continues to thrive,” Cottingham said.

However, Uber maintains that Atlanta’s plan would add “substantial, additional bureaucratic barriers for drivers,” company spokesman Bill Gibbons said. Atlanta would use the Georgia Department of Driver Services to help check the backgrounds of potential drivers, though specific details of how drivers would be screened haven’t been released.

The ride-booking firm Lyft also says Atlanta’s proposal would prove difficult to implement.

“While the Hartsfield-Jackson staff has recognized the benefits Lyft provides, the current plan as proposed will make it extremely difficult for Lyft to operate,” Lyft said in a statement to The Associated Press.

The conflict in Atlanta is the latest in a series of disputes Uber has had over its background checks of drivers.

In December 2014, San Francisco district attorney George Gascón and Los Angeles County district attorney Jackie Lacey announced a lawsuit against Uber, partly over its background checks.

In Los Angeles, “registered sex offenders, a kidnapper, identity thieves, burglars, and a convicted murderer had passed Uber’s ‘industry leading’ background check,” the lawsuit states.

“Uber’s process cannot ensure that the information in the background check report is actually associated with the applicant since it does not use a unique biometric identifier such as a fingerprint,” the lawsuit adds.