Google has banned cryptocurrency mining browser extensions from the Chrome store.

The U.S. tech giant announced its decision on Monday, and said that in July it will start removing existing browser extensions that facilitate mining. Other blockchain-related extensions are still allowed.

Google previously permitted Chrome mining extensions as long as they were solely dedicated to mining and explicitly informed users of their purpose. But that policy wasn’t enough to deter or keep out noncompliant add-ons.

Forum posts from The Chromium Projects – an open-source initiative started by Google to furnish source code for Chrome – show that developers have been concerned about mining extensions since last autumn.

According to Wired, Google decided to implement Monday’s ban because the majority of mining extensions submitted to the Chrome Web Store failed to comply with its sole-usage policy.

“The key to maintaining a healthy extensions ecosystem is to keep the platform open and flexible,” James Wagner, Google’s extensions platform product manager told Wired. “This empowers our developers to build creative and innovative customizations for Chrome browser users.” He explained further:

“This is why we chose to defer banning extensions with cryptomining scripts until it became clear that the vast majority of mining extensions submitted for review failed to comply with our single purpose policy or were malicious.”

The mining extension ban comes less than a month after Google announced its plans to ban cryptocurrency-related advertisements.

Clandestine cryptocurrency mining has become increasingly common in recent months, with governments and major companies alike suffering from attacks.

In February, for example, electric vehicle maker Tesla’s cloud was compromised by mining malware. U.K. government websites were also exploited by mining malware around the same time.

In January, cybersecurity firm TrendMicro discovered that Google itself was a victim, and that its DoubleClick Ads were used to distribute crypto mining malware.

Google Chrome app image via Shutterstock