DENVER (AP) — Colorado marijuana regulators are finalizing a ban on certain additives in cannabis vape products in response to the spread of a lung disease linked to e-cigarettes and marijuana vape pens.

The Denver Post reports the state’s Marijuana Enforcement Division has proposed final rules that include prohibiting specific ingredients in marijuana vaping products.

The updates are expected to be discussed during a public hearing Tuesday.

The ingredients include Polyethylene glycol, Vitamin E Acetate and Medium Chain Triglycerides.

Officials say the additives can be used as thinning agents for THC, which is too thick to be atomized or vaporized in vaping products.

A vaping-related lung disease has sickened nearly 1,300 people and killed at least 25 nationwide.

State health officials say there were nine cases reported in Colorado as of last week.