Every state that has legalized marijuana makes its own choice about whether and what warnings to include on packaging/labeling.

Why it’s important: States often do not require a comprehensive set of warnings.

The findings: Many states require specific texts and warnings to appear on marijuana packaging, but not all do. A study found that…

Only 11 states (of the 25 with legal marijuana) require packages to have a warning about keeping the product away from kids. Many require packages to be child-resistant without including such warnings.
Warning labels about consumption by pregnant women are required by 9 states.
10 require labels warning about impaired ability to drive.
6 mandate warnings about the general physical health risks, but only 1 requires warnings about the health risks for lungs associated with smoking.
Only 1 state requires warnings about the risk of psychosis, but several require warnings on marijuana being addictive/habit-forming.
4 states require warnings that the effects of marijuana could be delayed and that possession may be illegal outside the state.

For more: Partnership to End Addiction did a similar analysis for requirements on warning labels and many other requirements designed to help protect kids.