As Covid wave pushes up demand, Costco limits purchases of toilet paper and water.

Last year, a frantic run on toilet paper that left store shelves bare across the United States became a symbol of the panic that seized Americans in the early days of the coronavirus pandemic.

Now, at least one big-box retailer is trying to prevent a repeat of that frenzy as the Delta variant has driven caseloads higher in many parts of the country.

The retailer, Costco, which is known for its bargains on bulk food and cleaning supplies, confirmed in a fourth-quarter earnings call on Thursday that it was “putting some limitations on key items” such as toilet paper, cleaning products and Kirkland Signature water.

The company did not specify what those limits were, but Richard A. Galanti, the executive vice president and chief financial officer of Costco, pointed to “the uptick in Delta-related demand.”

He said that supply chains had also been affected by “port delays; container shortages; Covid disruptions; shortages on various components, raw materials and ingredients; labor cost pressures, and trucker and driver shortages.”

“A year ago, there was a shortage of merchandise,” Mr. Galanti said, according to a transcript of the call posted on The Motley Fool website. “Now they’ve got plenty of merchandise, but there’s two- or three-week delays on getting it delivered.”

To keep store shelves filled, Costco has been “ordering as much as we can and getting it in earlier,” Mr. Galanti said. The company has chartered three ocean vessels to transport containers between Asia and the United States and Canada, he said. Each ship can carry 800 to 1,000 containers at a time.