The US Food and Drug Administration on Monday issued a first-of-its-kind alert to try to block the import of toxic hand sanitizers from Mexico, which have been flooding the market amid the COVID-19 pandemic.

Last June, the regulatory agency began issuing alerts and warnings for consumers about dangerous and counterfeit hand sanitizers, many of which were made in Mexico. Since then, the FDA has issued alerts on 226 products. An FDA survey conducted between April and December found that 84 percent of products tested from Mexico were not in compliance with FDA regulations.

Many of the concerning products are labeled as containing safe alcohols but actually contained methanol, an extremely poisonous form of alcohol associated with incorrectly distilled liquors that can cause blindness and even death. The FDA discovered some other products containing another toxic ingredient, 1-propanol, while others simply contained insufficient amounts of safe alcohols for sanitation. (Safe alcohols for hand sanitizers include ethanol, aka ethyl alcohol, at concentrations above 60 percent or isopropyl alcohol at concentrations above 70 percent.)

Along with spotting the dangerous products, the agency also said it began getting reports from states of methanol poisonings from sanitizers, which in some cases lead to blindness, cardiac effects, effects on the central nervous system, hospitalizations, and deaths in adults and children. The agency notes that methanol exposures can cause nausea, vomiting, headache, blurred vision, permanent blindness, seizures, coma, permanent damage to the nervous system, or death. Though the products pose risks to anyone using the sanitizers properly—they can be absorbed through the skin—the products are most dangerous to small children who may drink them out of curiosity or adults who drink them as an alcohol substitute.

The import alert issued Monday will allow the agency to detain any suspect incoming products at the border so that the regulatory agency can give them a more thorough safety review. In its announcement of the alert, the FDA noted that it marks the first time in the agency’s history that it has issued a countrywide import alert for any category of drug product.

“Consumer use of hand sanitizers has increased significantly during the coronavirus pandemic… and the availability of poor-quality products with dangerous and unacceptable ingredients will not be tolerated,” Judy McMeekin, the FDA’s associate commissioner for regulatory affairs, said in the announcement.

Below is a sampling of some of the offending products, and the full list can be found here. If you find you have any of the products on the list, stop using them immediately. If you have any concern about a possible toxic exposure, contact your poison control center and/or seek immediate medical treatment. Any toxic hand sanitizers should not be flushed or put down the drain; instead, they need to be disposed of in an appropriate hazardous waste container.