Although many people use Uber to avoid getting behind the wheel after having a few too many drinks, regulators in California say the ride-hailing company put passengers and the public at risk by failing to quickly boot drivers accused of accused of working while under the influence from its platform.

According to an order [PDF] released this week, the California Public Utilities Commission has opened an investigation into Uber, alleging that the company repeatedly violated the commission’s safety requirements by failing to comply with zero-tolerance rules for its drivers.

An investigation by the CPUC’s Consumer Protection and Enforcement Division found that of 154 complaints it reviewed involving drivers accused of driving under the influence between 2014 and 2015, Uber failed to suspend — or even investigate — drivers in a total of 151 complaints.

According to CPUC rules, Transportation Network Companies like Uber are required to comply with a policy that includes suspending any driver for further investigation “promptly after a zero-tolerance complaint is filed.”

Out of the 154 complaints CPED reviewed, Uber provided evidence for only 22 instances when it suspended a driver within an hour of a passenger filing a complaint. But even then, the commission claims, Uber’s records appear to contradict that.

For example, officials say in one instance where Uber had apparently suspected a driver, other records indicate that the driver stayed logged in on the app, and was available to pick up passengers for two hours following the suspension. He provided one ride in the first hour, and then responded to four more requests, providing two additional rides.

The commission’s investigation also determined that Uber doesn’t provide a way for passengers to flag a complaint as a possible drunk driving situation. Instead, the company has to first review each complaint to determine whether it contains such an allegation. If it does, Uber then has to take action on the driver’s account and suspend them from the platform.

That’s a flawed approach, the commission claims, as it’s open to human error, and is contrary to CPUC’s safety policy requiring prompt suspension as soon as a zero-tolerance complaint is filed.

In some cases, CPUC says, Uber checked in with a passenger later to question whether they really meant to file a zero-tolerance complaint. That practice contradicts the commission’s rules that say a TNC has to suspend any driver accused of driving under the influence before investigating the complaint.

“The Commission does not require TNCs to verify the validity of the complaint before suspending the driver,” CPUC says.

The commission claims Uber placed “passengers and the public at immediate risk” by allegedly allowing drivers to remain on the platform, and is recommending a fine of 7,500 for each of those 151 alleged violations, for a total penalty of $1,132,500.

In an statement to The Mercury News, Uber says it’s assessing its options regarding the potential fine.

“We have zero tolerance for any impaired driving as outlined in our Community Guidelines,” an Uber spokeswoman said in the statement. “This report relates to complaints in 2014 and 2015 and we’ve significantly improved our processes since then.”

This isn’t the first time Uber has faced a stiff fine from the CPUC: In 2016, the company had to pay a penalty of $7.6 million after a judge found it had failed to meet data reporting requirements.

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