While the company did not address the nationwide total, it issued a statement of sympathy about the death of the employee in Quincy. “There are no words to express the loss of our associate, and we are mourning alongside their family," the company said in a statement on Tuesday.

“Every worker in a retail job that we know right now is terrified,” said Gillian Mason, co-executive director of the worker advocacy group Massachusetts Jobs With Justice. “Walmart can’t turn its stores into petri dishes where workers are constantly at risk.”

The sheer number of cases in Worcester makes it one of the largest outbreak clusters in the state, and among the largest at any retailer in the country. How it happened — despite social distancing measures, temperature screenings, and other CDC recommended guidelines — is a reminder of just how easily the virus can spread, public health officials say, and it should serve as a warning to all businesses looking to reopen in the wake of the crisis.