Workers seeking to invoke the so-called conscience protection would have to provide reasonable notice.
Gov. Jay Nixon objects to the bill because it would raise the state sales tax by one-half cent over five years.
The final measure was the product of a compromise forged after nearly eight hours of opposition from Senate Democrats.
Websites have been set up to alert people when a decision is made, and several media outlets are broadcasting from the scene.
James Holmes is charged with 166 counts, mostly murder and attempted murder, in the July 20 attack on moviegoers at a midnight showing of "The Dark Knight Rises" in the Denver suburb of Aurora that killed 12 people and injured 70.
Mike Griggs, the department's current assistant director, will be promoted to the position effective Friday.
Revenue from the bonds could pay for construction on college campuses, state parks, the state Capitol and rural water projects.
The legislation is the work of a Missouri Bar panel that began meeting five years ago to give the code its first makeover since the 1970s.
Curiosity is the first spacecraft sent to Mars that could collect a sample from deep inside a rock, and scientists said Tuesday that they hit pay dirt with that first rock.