The 148th most popular book on Amazon Wednesday wasn’t actually a book at all: It was a package of 50 disposable face masks—the kind that shoppers have scrambled to buy amid the coronavirus pandemic. Surging demand for masks, as well as supplies like hand sanitizer and disinfectant wipes, has emptied store shelves, and in some cases led to skyrocketing prices on Amazon.

The box of masks had risen in sales rank from 19,662 to 148 in just one day, according to Amazon’s list of “Movers & Shakers,” or goods that have surged in popularity in a given category in the past 24 hours. A similar scenario played out the next day: The number two Mover & Shaker in the videogames category Thursday morning, beating out The Sims 4 and a gaming headset, was a package of 50 disposable face masks. Both of these product listings for masks appear to violate Amazon’s rules.

“Face masks and hand sanitizers are the number one and number two most searched terms on Amazon. That's attracting many sellers who are pulling every trick they can think of to get into search results,” says Juozas Kaziukėnas, founder of the ecommerce data firm Marketplace Pulse, who first alerted WIRED to the face mask listings.

"Bad actors that attempt to abuse our systems make up a tiny fraction of activity on our site," a spokesperson for Amazon said in a statement. "We use sophisticated tools, including machine learning, to combat them, and we are making it increasingly difficult for bad actors to hide. These bad actors show a flagrant disregard for our community, our policies, and in some cases, the law, and do not reflect the flourishing community of honest entrepreneurs that make up the vast majority of our sellers."

A screenshot of Amazon's Movers & Shakers page on Wednesday afternoon. Courtesy of Amazon

The company began cracking down on third-party sellers seeking to exploit the pandemic last month, warning them not to engage in price gouging, or risk getting kicked off the site. By the end of February, Amazon announced it had removed 1 million products that were falsely advertised to defend against or cure Covid-19, as well as tens of thousands of items listed for inflated prices. Senator Ed Markey, the Democrat from Massachusetts, sent a letter to Amazon earlier this month asking about price gouging, and attorneys general across the country say they have received hundreds of complaints about the practice.