SAN FRANCISCO — Glassdoor Inc., the operator of the anonymous job review website, is facing down a massive class action after inadvertently revealing the email addresses of hundreds of thousands of users by failing to “blind CC” recipients on a mass email.

The Sausalito, California-based company was sued Monday afternoon in a Los Angeles federal court by attorneys at Geragos & Geragos who argue that the company endangered the jobs of users whose email addresses were exposed by mistake on July 22.

“Glassdoor has made billions of dollars on the supposedly anonymous reviews of companies supplied by its members,” the complaint says. “Instead of safeguarding the identities of its members … Glassdoor carelessly provided the emails of 600,000 [members] to the public, violating the trust placed in them and opening up its members to retaliation.”

The suit alleges violations of the Federal Stored Communications Act, which it says bars the kinds of disclosures that Glassdoor committed, as well as general privacy and negligence violations. It seeks damages for all of the users affected by the leak.

A Glassdoor representative declined to comment directly on the lawsuit. But in previous statements the company expressed regret for the leak, which it called an “error.”

“As we’ve previously disclosed, a small percentage of Glassdoor registered users’ email addresses were viewable in the “to” field to a subset of other users who received a routine email. No other information was viewable or revealed. We have directly apologized to the affected users,” a company spokeswoman wrote Monday in an email. “We do take the privacy of our users very seriously and are taking corrective steps to ensure this doesn’t happen again.”

The leak occurred when Glassdoor sent out a new terms of service to its users. Instead of copying to them blindly, each email showed the addresses of 999 other recipients, the complaint says. The company has said the mistake exposed the email addresses of about 2 percent of its user base.

The lawsuit was filed on behalf of Melissa Levine, a Los Angeles resident who says her email address was exposed. The complaint emphasizes that Glassdoor has gone to lengths to characterize itself as creating an “anonymous community” where users can freely express their views about their current and former workplaces.

The whole incident puts Glassdoor in an awkward position. The Mill Valley, California-based company has fought to defend the privacy of its users and earlier this year, it successfully fended off an attempt to expose the identities of people who posted negative comments about an Illinois business.

Geragos & Geragos is probably best known for representing celebrities like Chris Brown and Michael Jackson. But the firm has been on the offensive recently in a string of suits against Internet-enabled businesses. It has sued online real estate Zillow Inc., and earlier this summer hit Snapchat with a class action alleging that it exposes minors to pornographic content without warning.

Ben Hancock can be reached at bhancock@alm.com. On Twitter: @benghancock