The probe discovered more than 4,000 items for sale on the company's site that have been declared unsafe by federal agencies, have misleading labels or are outright banned by federal regulators. The site shows numerous listings for toys and medications that don't include warnings about health risks to children, as well as sleeping mats previously banned by the FDA over concerns that they can suffocate infants, the Journal reported.
Following the report, Amazon removed or changed the description on more than half of the problematic listings, according to the Journal.
The company said in a blog post responding to the investigation that it requires products on its site to comply with "relevant laws and regulations." It also pointed to its use of automated tools that scan for noncompliant products.
"We have a dedicated global team of compliance specialists that review submitted safety documentation, and we have additional qualification requirements that sellers must meet to offer products," the company said in the blog post. "In 2018, our teams and technologies proactively blocked more than three billion suspect listings for various forms of abuse, including non-compliance, before they were published to our store."
The investigation underscores Amazon's difficulty overseeing the millions of third-party sellers on its platform. Earlier this year, the company changed its quality control standards for school supplies and children's jewelry sold on the site after an investigation by Washington Attorney General Bob Ferguson found they had unsafe levels of toxic metals. In recent years, the company has also struggled to root out counterfeit products and accidentally punished legitimate sellers after rivals reported them as selling counterfeits, CNBC has previously reported.
In the past, U.S. courts have said Amazon is not liable for claims related to third-party products sold on its marketplace. In June 2018, for instance, a judge in Tennessee ruled for Amazon in a case where a hoverboard purchased on the marketplace exploded and burned a family's house down. The judge wrote, "Amazon's role in the transaction was to provide a mechanism to facilitate the interchange between the entity seeking to sell the product and the individual who sought to buy it."
Read the full report at The Wall Street Journal.