Many of the country’s largest retailers will keep requiring masks in their stores despite eased national restrictions, though industry groups and workers’ advocates fear enforcement will become increasingly difficult and contentious.

The U.S. Centers for Disease Control and Prevention announced Thursday that fully vaccinated Americans no longer need to wear masks in most situations. Workers unions blasted the policy change, saying it creates confusion and puts store employees at increased risk of getting sick.

Target, Home Depot, Harris Teeter and Wegmans Food Markets are among the chains that will continue to require masks in store, though they are reviewing new CDC guidance and reevaluating store policies.

Others, like Trader Joe’s, have updated their policies and will no longer require fully vaccinated shoppers to wear masks, though it was unclear how the retailer would determine which shoppers have been inoculated. Kenya Friend-Daniel, a spokeswoman for the grocery chain, said most other COVID-related policies, including face coverings for employees, social distancing rules and frequent store cleanings, will remain in place.

“We are vigilant; reviewing federal, state and local health advisories; meeting or exceeding government mandates; and where it makes sense, adjusting efforts,” the company said on its website.

The Retail Industry Leaders Association said the CDC’s revised guidelines conflict with some state and local orders, creating ambiguity for retailers and their employees.

“We urge all retail customers and guests to follow a store’s safety protocols including wearing a mask and social distancing,” Lisa LaBruno, a senior executive vice president for the trade group, said in a statement. “Frontline workers deserve this respect. Retailers encourage customers that do not want to wear a mask to shop online or via curbside pickup offerings.”

The United Food and Commercial Workers, which represents 1.3 million food and retail workers, said the CDC’s guidance fails to consider the impact on essential workers “who face frequent exposure to individuals who are not vaccinated and refuse to wear masks.” More than 200 retail workers have died from the coronavirus, and thousands more have been infected, according to workers groups and media reports, though actual numbers are probably much higher.

“Vaccinations are helping us take control of this pandemic, but we must not let our guard down,” Marc Perrone, the union’s president said in a statement. “Essential workers are still forced to play mask police for shoppers who are unvaccinated and refuse to follow local COVID safety measures. Are they now supposed to become the vaccination police?”