Under the California Environmental Quality Act, anyone who participated in the public comments or hearings about an environmental impact report can sue whatever authority approves some project. That is why in California every EIR on any project of any kind will gather some public comments from union members. The unions are preserving their standing to sue at a later time.

Typical example is this letter sent by lawyers on behalf of labor unions, commenting on the EIR of a solar project.

https://phonyuniontreehuggers.com/wp-content/uploads/2016/01...