A Gillette spokesman, Eric Kraus, said the company was looking into labor practices at the plants, which are run by two packaging contractors, Sonoco and Markson Rosenthal, both in Fort Devens, a former Army base 23 miles southwest of Lawrence. Mr. Kraus said that a law firm hired to investigate the matter would issue a detailed report in November.

"We expect all of our vendors to conduct business to the highest ethical standard, the same high standard we hold Gillette to," he said. "We stress that this is their responsibility to implement and enforce."

Mr. Kraus said Gillette had subcontracted its packaging operations to companies with more expertise in that area so it could concentrate on manufacturing razors and blades.

Allan V. Cecil, a senior vice president at Sonoco, said that reports of workplace abuses were unfounded and that his company had no intention of rethinking its heavy reliance on temporary workers.

"It's a business model that requires a temp work force," Mr. Cecil said. "A year ago last October, we had zero temps, and then it can go to 700, 800. There are dramatically big swings depending on the workload."

No one from Markson Rosenthal responded to interview requests.

Mr. Hiciano, a doctor who left the Dominican Republic five years ago to seek a more prosperous life, said it was unfair for employees to work year after year on a temporary basis. He said Sonoco's managers had repeatedly told him they would not employ him as a permanent worker because he did not speak English. But he said that many permanent employees knew little English.

"A temp worker doesn't have secure work, doesn't have health insurance or many benefits," he said in Spanish. "Some weeks you work only three, four days. If you're a temp and you make a mistake, they let you go. If you're a permanent worker and you make a mistake, they take you aside and tell you how to do it better."