The Centers for Disease Prevention and Control this week warned employees to avoid arguing with customers who are not following mitigation measures like mask wearing and who threaten to get violent.

“Workers may be threatened and assaulted as businesses try to put into place COVID-19 prevention policies and practices (e.g., mandatory use of masks, social distancing, and limits on the number of customers allowed in a business),” the CDC said in its guidance. “These threats and assaults can come from customers, other employees or employers.”

Workers should not argue with a customer if they make threats or become violent, the CDC advised. They also shouldn’t try to force people to follow the coronavirus mitigation measures if they appear upset or violent.

Many stores are left to their own devices to enforce mask requirements with more than half of states mandating they be worn in public.

Videos and accounts of confrontations between anti-mask customers and employees – some of which have turned violent – have circulated online, despite research finding that mask wearing can save lives. Mask wearing, which has been shown to limit the spread of potentially infectious respiratory droplets, has been seen by some as a political choice.

Several large retailers have issued their own mask requirements. However, a handful of stores, including Walmart and Home Depot, said they will still serve customers who refuse to wear masks, citing a desire to avoid confrontations.

While threats and assaults can happen in any workplace, the CDC said it is more likely to happen in customer-based businesses like restaurants and retail stores. These actions can include yelling, swearing, hitting, slapping and choking.

The agency listed a number of steps employers can take, which include training on threat recognition and conflict resolution, installing security cameras and assigning two employees to work as a team to enforce coronavirus mitigation measures, if possible.