ProPublica and NPR published another joint investigation of the workers' compensation system Wednesday, focusing this report on a Florida law that criminalizes undocumented workers who seek workers' compensation benefits.

Passed in 2003, the law makes applying for workers' compensation benefits with an invalid Social Security number a felony. Insurers have since made it standard practice to turn in undocumented workers to the state after injuries rather than paying for benefits. 

The law has also allowed the state to charge undocumented workers with felony workers' compensation fraud even if they have not sought workers' compensation benefits. Simply having a false Social Security number is enough to substantiate the charge. 

ProPublica and NPR identified nearly 800 cases where employees were arrested under the law. At least 25% of those arrested ended up detained by Immigrations and Customs Enforcement or deported.

A state insurance agency executive said the law was not designed to target undocumented workers. Nonetheless, a review by NPR and ProPublica, corroborated by a report from the insurance department's Division of Investigative and Forensic Services, showed that more than 99% of the workers arrested under the statute were Hispanic immigrants working with false papers. 

ProPublica and NPR previously reported on the workers' compensation system in a series called "Insult to Injury: America's vanishing worker protections," whose first stories ran in 2015.