New York CNN Business  — 

Top US retail and food chains have updated their mask policies since the US Centers for Disease Control and Prevention said this week that fully vaccinated people should wear masks indoors in areas with substantial Covid-19 transmission.

That designation includes more than two-thirds of US counties. The CDC changed its guidance in response to the rising spread of the new, highly transmissible Delta variant and low vaccination rates in many areas of the country.

Mask policies have challenged stores throughout the pandemic and led to disputes between opponents of masks and frontline workers trying to enforce safety measures. Most large chains had removed face covering requirements for vaccinated shoppers in May, following CDC guidance at the time easing mask-wearing for people vaccinated. Stores have continued to ask unvaccinated shoppers to wear masks.

Here are the updated mask rules at some of the biggest stores in America:

Walmart

In counties with substantial or high risk of transmission and where there are state or local mask mandates, Walmart workers will be required to wear masks inside its facilities, including stores, Sam’s Club locations, and distribution and fulfillment centers.

Walmart is asking shoppers to wear masks inside stores in counties deemed at high risk, but not requiring it. Walmart will also post signs to remind customers about the CDC’s revised guidance and encourage them to wear masks.

Target

Target will require masks for workers and recommend masks for all customers in areas with substantial or high risk of transmission.

“We’ll follow all local mandates, as we have throughout the pandemic, and continue to monitor guidance from the CDC closely,” Target says.

Costco

Costco “strongly recommends that all members and guests wear face masks inside our locations” in areas with high or substantial transmission risk, according to the company’s website. Costco will not require masks.

Home Depot

Home Depot is requiring all workers to wear masks in all stores, regardless of vaccination status or the transmission risks of the area.

“We’ll ask customers to wear masks while in our stores and continue to offer masks to those who don’t have one,” Home Depot says.

Kroger

Kroger “strongly encourages” all workers and customers to wear a mask in stores and facilities, but does not require them.

“We will continue to abide by all state and local mandates and encourage all Americans to get vaccinated, including our associates,” the company says.

McDonald’s

McDonald’s told CNN on Tuesday that customers and staff inside restaurants in areas with high or substantial transmission will be required to wear a mask, regardless of vaccination status. The chain added the policy change reflects CDC guidance.

The fast-food giant also said masks have already been required for staff and customers who are not vaccinated.

Starbucks

Starbucks recommends customers wear facial coverings, regardless of vaccination status, the company says.

Where mandated by local law or regulation, Starbucks will require customers wear masks in our stores.

Starbucks employees are also required to wear masks on their shift.