LANSING, Mich. (AP) — Michigan has temporarily halted the sale of marijuana products intended for vaping so that they can be tested for a compound linked to lung illnesses.

The Marijuana Regulatory Agency issued the emergency rules Friday.

They prohibit licensed medical and recreational marijuana businesses from selling existing products intended for e-cigarette use unless they are re-tested and do not have vitamin E acetate. Newly made vaping products cannot have the compound, either.

Regulators plan to inspect processing facilities twice a month to make sure they do not contain inactive ingredients that are not approved by the U.S. Food and Drug Administration for inhalation.

Vitamin E acetate has only recently been used as a thickener in vaping fluid, particularly in black market vaping cartridges.