LOS ANGELES — An alliance of major legal marijuana businesses in California is urging the state to adopt tougher safety rules for ingredients and devices used in vaping.

Recommendations from the industry group — Legal Cannabis for Consumer Safety — follow a national outbreak of mysterious and sometimes fatal lung illnesses apparently linked to vaping. Most cases have involved products that contain the marijuana compound THC, typically obtained from illegal sources.

In a letter to Gov. Gavin Newsom, the group says it’s eager to heighten the safety of cannabis vaping while seeing more funds devoted to closing illegal pot shops.

Among its proposals, the group says regulations should expressly ban the use of additives, cutting agents and artificial flavoring known to be harmful in cannabis vaping products.