(Reuters) - Two chemical and plastics industry groups each filed a lawsuit against California Attorney General Rob Bonta on Friday, seeking to block his attempt to force them to hand over documents as part of an ongoing probe into the plastic waste crisis.

The American Chemistry Council and Plastics Industry Association filed their lawsuits in a Washington, D.C., federal court, claiming California's Democratic top lawyer's demands have chilled their constitutional right to free speech, among other things.

The groups said they had already provided some documents on things like public newsletters and public remarks about "advanced recycling" technology, which uses a process called pyrolysis to turn hard-to-recycle plastic into fuel.

They have withheld internal documents they said contain confidential industry data and communications related to public policy and advocacy matters.

They said Bonta has abused his authority by demanding the additional documents, and are seeking an order enjoining him from taking further investigative actions against them.

Bonta's office and the industry groups did not immediately respond to requests for comment.

California launched its investigation into the oil and petrochemical industry's role in creating and exacerbating the global plastic waste crisis in April 2022. Bonta said last month his office would decide whether to sue Exxon, a key focus of the investigation, by the summer.

California has taken similar legal actions on climate change, focusing on what the fossil fuel industry knew about that problem for decades and how it misled the public about its role.

More than 90% of plastic waste globally ends up in landfills or is incinerated, according to a landmark study published in Science Advances. The U.S. recycling rate has never gone higher than 9%, according to the Environmental Protection Agency.

A Reuters investigation found that advanced recycling projects worldwide had faced numerous delays and failures even as companies touted their success.

(Reporting by Clark Mindock; Editing by Richard Chang)

By Clark Mindock