Authored by Senate commerce committee members Bob Menendez (D-NJ), Ed Markey (D-MA) and Richard Blumenthal (D-CT), the letter also called for the ecommerce giant to immediately remove the illicit items. “Unquestionably, Amazon is falling short of its commitment to keeping safe those consumers who use its massive platform. We call on you to immediately remove from the platform all the problematic products examined in the recent WSJ report, explain how you are going about the process, conduct a sweeping internal investigation of your enforcement and consumer safety policy; and institute changes that will continue to keep unsafe products off your platform,” wrote the lawmakers. Earlier this month, Menendez and Blumenthal sent a letter to the retail giant inquiring about its “Amazon Choice” program and why faulty or inferior products sometimes receive the touted classification.

The WSJ investigation found at least 2,000 listings on Amazon for toys and medications that lacked warnings about health risks to children. Reporters also unearthed toxic paint strippers, infant sleeping mats linked to suffocation, dietary supplements containing illegal prescription drugs, toys containing lead and products that falsely stated they were cleared by a federal agency.

The report recounted an incident in which a 23-year old wearing a helmet purchased on Amazon died in a 2014 motorcycle crash. The helmet, which came off of the man during the crash, had been fraudulently listed as certified by the Department of Transportation.

The senators also asked Amazon for an explanation of why its current safety protocols failed, and what it will do to prevent selling unsafe products in the future. In response to the WSJ article, Amazon published a blog post about its existing safety and compliance program but made no promises that it would change its protocols.

According to CNET, Amazon said it plans on answering the questions posed by senators in the letter. The WSJ reported today that Amazon appeared to remove or modify some of the dangerous items, but some of them have since resurfaced under new listings.

“We are concerned the badge is assigned in an arbitrary manner, or worse, based on fraudulent product reviews. While, we recognize that Amazon has taken actions in the past to combat fraudulent reviews — the problem persists — and Amazon may be exacerbating the problem by actively promoting products with fraudulent reviews,” wrote the senators. A list of questions sought specific details on how items get selected for the program, including whether an algorithm is informing Amazon’s decision-making and if products are reviewed by humans to ensure they’re of high quality.

A recent Buzzfeed investigation revealed how many inferior Amazon Choice products thrived on hundreds of fake or misleading reviews. These items included an AmazonBasics Security Safe which could be easily opened with a tool and a flask that turned alcohol black. A fake review of a thermometer recommended it for babies — despite the fact that the product’s details explicitly state it is not intended for newborns.

Amazon first debuted its Amazon Choice program back in 2015 as a way to select the default products for customers who order through the Echo speakers. The label’s description on the website reads, “Amazon’s Choice recommends highly rated, well-priced products available to ship immediately.” But rather than simply select the highest-rated bath towel or jade roller for the Choice label, Amazon appears to take other, undisclosed metrics into consideration.

Amazon must respond to the lawmakers’ queries by September 16th. The senators will then decide whether the situation warrants further any action, such as legislation. “Senator Menendez would like to see what are the responses to their questions and then see if there’s anything the federal government needs to do if they fail to correct their behavior,” wrote Menendez’s communication director Francisco Pelayo in an email to Engadget.