Yet this year, the California Environmental Quality Act has become a target for sweeping changes in the Legislature. Democrats who typically align with environmental groups are taking seriously the concerns that have long been raised by business leaders.

Critics say the act is being used well beyond its intended purpose and instead is employed by unions, activist groups and even rival developers to delay or stop projects they don’t like. Business leaders are now joined by groups supporting affordable housing, mass transit and public works.

The law’s supporters say it leads to modifications that prevent harmful consequences while giving the public information about potential changes to their neighborhoods and business districts.