Mask mandates have been accepted by most, but are still being challenged aggressively by others, leaving employees and customers at grocery chains across the city fed up with backlash against rules beyond their control.

A group of mask-less protestors stormed a San Diego Trader Joe’s on April 13, harassing employees and customers, becoming so aggressive law enforcement was called -- all because of laws requiring mask wearing inside the store.

The event marked the second attempt by the group to enter the store without a mask.

The Trader Joe’s is one of several San Diego grocery stores defending their doors from anti-maskers protesting mask mandates as California enters a less restrictive phase of the pandemic.

“I fully understand the right to protest. We do it all the time, but we do it out in the public…we don't protest the workers. The workers have nothing to do with this,” said Todd Walters, president of the United Food and Commercial Workers Union Local 135. “These poor workers can't comment…they're in fear of losing their jobs if they dare to respond or worse than that, they still have to do their job and they're being harassed by somebody who's in their face.”

Walters told NBC 7 it’s important that employees know they have rights.

“You have the initial right to remove yourself from an unsafe situation, if somebody is in your face and you feel it's unsafe, they cannot terminate you for insubordination," he said.

One frequent customer at the Trader Joe’s, who asked not to be named, told NBC 7 she’s seen the emotional toll these encounters have taken on staff -- some of whom say they’ve had to be escorted to their cars by police after their shifts end and were fearful of retaliation if identified in this story.

“They are really affected emotionally by some of these events,” she said. “The community's been rattled, and we just want to stand up for our hard working essential workers.”

Another customer told NBC 7 she frequents the store two to three times a week and prefers that store over others because of how consistent staff is with taking safety precautions seriously. She said she hopes management doesn’t cave to the demands of protestors or she will have to shop elsewhere.

California started requiring mask wearing inside businesses in June of 2020. The mandate, despite sparking debates throughout the pandemic, has made an impact, according to data from the Centers for Disease Control and Prevention.

Last week California’s COVID-19 case rate became the lowest of any state, leaving the first state to implement a lockdown on track with plans to fully reopen in June.

Still, Walters wants people to be patient and stop the harassment.

“I'm looking forward to the day when I don't have to wear my mask anymore, you don't have to wear your mask anymore, we can all move on,” he said. “The workers in these retail stores are just trying to make a living, feed their families, do their job and go home. Quite honestly, they don't like wearing the masks either and that's what everybody needs to understand.”

Community members told NBC 7 they’re concerned the anti-mask protestors will continue testing these grocery chains until they are allowed inside without a mask to avoid conflict despite proper mask guidelines.

The San Diego Police Department told NBC 7 in situations like this, they can’t act proactively, but can only react by sending officers when a business has called and requested help.