Workers at grocery stores and warehouses deemed “essential businesses” amid the Covid-19 outbreak have expressed concern that showing up to work puts them at risk of contracting the disease. In recent days, a number of retailers have said they will provide workers with masks, but sourcing such protective equipment has proved difficult as hospitals and health workers also struggle to get their hands on such gear.Walmart, the largest private employer in the United States, has waited to secure protective gear to avoid limiting equipment that could go to strained health workers, Dan Bartlett, the company’s vice president of corporate affairs, told reporters. The company will need more than seven million masks each week for its employees, he said. The first shipment will arrive in one to two weeks.Walmart on Friday announced several additional steps it is implementing in an effort to lower the risk of spread in its stores.The company is reducingt the number of customers that can enter stores at one time, using floor markers to enforce social distancing and establishing designated entrance and exit doors. Walmart previously announced measures including paid leave for workers amid the coronavirus outbreak, employee temperature checks and limited store hours to allow for cleaning and restocking.