Workers for Instacart, a grocery shopping and delivery app, are expected to walk off the job in cities across the country, including in the Greater Boston area, on Monday in protest of what they say is the company’s refusal to offer basic health protections and paid sick leave at a time when it has seen unprecedented growth.

As efforts to combat the novel coronavirus pandemic confined most of the world indoors, the app — which employs full-time and part-time workers called "shoppers" — is more popular than ever.

In recent days, visitors to the Instacart website who ordered at grocery stores in the Boston area, such as Market Basket, received an auto-response message saying, "Sorry! No times are available. ... Demand is higher than normal now."

The speed to meet that demand and the absence of protections like gloves, masks and anti-viral hand sanitizer has left Instacart workers vulnerable to the virus, strike organizers said.

Workers are demanding free hand sanitizer, disinfectant wipes and soap as well as hazard pay of an additional five dollars per grocery order. They also demanded paid sick leave for workers with pre-existing conditions.

Instacart, which employs 175,000 gig workers to shop in supermarkets and hardware stores across the country, said in an email to WGBH News that it will provide additional bonuses and better health protections for its gig workers, among other concessions.

In its statement, Instacart added that the company “has been taking proactive measures to maintain a safe environment for [Instacart workers] nationwide, including working closely with local teams to provide disinfecting supplies for in-store shoppers and sanitation stations in collaboration with retail partners.”

One local Instacart shopper is Matt, who asked that WGBH News not use his last name for fear of reprisals from the company and the supermarket where he is based: Star Market.

On Saturday, as streams of customers lined up at cash registers, hundreds more were relying on Instacart "shoppers" to plunk items from the shelves, sort them and bag them for delivery or pickup. Matt, who is in his 20s, rushed down various aisles loading up carts with juice, paper towels, canned soup and what was left of the toilet paper. Noticeably, he was not wearing gloves and seemed unconcerned about the novel coronavirus and the disease it can lead to, COVID-19.

“I feel that if I would have gotten it, it would have already happened, 'cause I’m in the public every day,” he said.

That view was echoed by another Instacart shopper named Mark, who was packing bags for pickup. Asked if he had concerns about his safety in the midst of a pandemic, he said he didn’t care.

“What am I going to do, go home and die, broke? I’d rather die working,” said Mark, whose last name WGBH News is also not using due to his fear of retribution.

Mark said he sympathized with Instacart workers who plan to walk off the job but that he would not be one of them.

“I can’t afford to go on strike," he said. "How am I going to eat and pay my rent?”