Since the early 2000s, Amazon has quietly received more than $1.5 billion in government subsidies, in exchange for bringing new jobs to cities and states across the country. At the same time, low-wage employees at Amazon's grueling warehouses have sometimes had to rely on a different kind of government benefit, like the Supplemental Nutrition Assistance Program, or food stamps, to make ends meet.

Now Senator Bernie Sanders is bringing renewed scrutiny to Amazon's reliance on taxpayer dollars to supplement wages. On Wednesday, the Vermont independent introduced the Stop Bad Employers by Zeroing Out Subsidies Act, which hits companies that have more than 500 employees with a 100 percent tax on some government benefits its workers receive, like public housing, Medicaid, and food stamps. For example: If the Stop BEZOS Act were to pass, McDonald’s would be taxed $100 every time one of its cashiers collected $100 in food stamps. The bill is designed to force large corporations to increase wages, and to raise awareness about how companies benefit from public welfare, even in a healthy economy.

The legislation would likely affect many large low-paying retailers, like Walmart and Home Depot, and also Amazon, which says it employs more than 125,000 full-time workers in its US fulfillment centers. The retail giant, which stayed silent amid President Trump’s repeated criticisms of the company, has mounted a public relations offensive in response to Sanders. Amazon even recently began instructing full-time “ambassadors” to promote positive stories about working in its fulfillment centers via a fleet of nearly identical Twitter accounts.

While Sanders is right to point out that many Amazon employees likely use public assistance to make ends meet, his new legislation doesn’t address the other kind of lucrative government benefits the retail giant often receives. In negotiating to open a new warehouse or other outpost, Amazon often obtains hefty tax breaks and other economic incentives from local politicians, the details of which aren’t always disclosed to taxpayers.

The Food Stamp Mystery

In the lead-up to the introduction of the Bezos bill, Sanders repeatedly singled out Amazon, now valued close to $1 trillion, for paying “employees wages that are so low that they are forced to depend on taxpayer-funded programs such as food stamps, Medicaid, and subsidized housing to survive.” He also invited Amazon warehouse workers to share their experiences with his office, some of which he later made public.

The initiative provoked a rare response from the retail giant, which in a blog post accused the senator of making “inaccurate and misleading accusations against Amazon.” In its response, Amazon took issue with Sanders’ claim that thousands of its workers rely on food stamps, arguing there’s no way to know if they’re employees who deliberately chose to work part-time or were seasonally employed. The company declined further comment on the legislation.

Amazon has a point. It’s impossible to know exactly how many workers at companies like Amazon use public benefits like SNAP, because many states don’t keep track, according to an investigation from news site The New Food Economy conducted by reporter Claire Brown.

She found that in five states, Amazon ranked among the top 20 companies with the most employees living in households that receive food stamps, even in places where it's not a top employer. But she was unable to obtain data from 25 additional states where she sought public records, in part because they don’t exist, at least not in a uniform manner.