JEFFERSON CITY, Mo. (AP) — More than 1 million low-income residents in 21 states could soon lose their government food stamps if they fail to meet work requirements that began kicking in this month.

The rule change in the federal Supplemental Nutrition Assistance Program was triggered by the improving economy — specifically, falling unemployment. But it is raising concerns among the poor, social service providers and food pantry workers, who fear an influx of hungry people.

Recent experience in other states indicates that most of those affected will probably not meet the work requirements and will be cut off from food stamps.

Advocates say some adults trying to find work face a host of obstacles, including criminal records, disabilities or lack of a driver’s license.

In Missouri, the GOP-led Legislature overrode a veto by Democratic Gov. Jay Nixon to enact a law barring the state from waiving work requirements until at least 2019. The three-month clock started ticking January 1st for 60,000 people in Missouri, where unemployment is down to just 4.4 percent.