Nevada regulators just released a health advisory warning customers to avoid specific brands of legal weed products that are contaminated with molds, yeasts, or fungus.

Last Friday, the state Department of Taxation announced that high levels of mold, yeast, fungus, and other contaminants were discovered in 19 different batches of legal pre-rolls or raw flower. These products were sold between October 25 and January 16 at legal dispensaries all across Nevada. But, over two-thirds of the shops carrying these products are located in Las Vegas.

Like other adult-use states, Nevada requires all legal cannabis products to undergo regular, thorough testing for contaminants to ensure that customers are not exposed to potentially dangerous products. But in 2017, just as adult-use sales were beginning, officials suspended the licenses of four testing labs for failing to follow proper procedures. One year later, the situation still hadn’t improved — 

state officials discovered that some legal weed products had yeast and mold levels nearly 40 times higher than the legal threshold.

Last September, officials launched another investigation into the integrity of the state’s licensed cannabis testing facilities. In December, the state shut down one of these labs, CANNEX Nevada LLC, after a thorough review of its lab practices. Officials discovered that CANNEX gave a passing grade to two strains of flower that tested for triple the allowable limit of mold and yeast, and issued another health advisory warning customers to stay away from these products.

The current health advisory covers 19 more batches of flower that were approved by CANNEX, even though they contained unsafe levels of contaminants. These bad batches of weed were grown by six different cultivators between last May and November, but there is no indication that the cultivators were intentionally trying to sell off their bad products as clean flower.

“There is no reason to believe these dispensaries or cultivators had any knowledge that the products exceeded allowable limits,” said the health advisory, according to the Las Vegas Review-Journal.

So far, state health officials have not linked any cases of illness with these contaminated products. Officials warn that consuming moldy weed still poses a health risk, however, especially for individuals with compromised immune systems.