HOUSTON (By Thayer Evans, NYTimes) June 26, 2008 — Federal immigration agents arrested 160 employees on Wednesday in a raid on a used clothing and rag exporting plant.

The authorities said it was the largest workplace raid ever here. Most of those arrested were from Mexico, El Salvador, Guatemala and Honduras, officials said, and 70 percent of them were women.

It was the second major raid in Houston in just over two months. Federal agents arrested 20 workers at a Shipley Do-Nuts factory on April 16.

The roundup on Wednesday at Action Rags USA, which is just north of the Houston Ship Channel, began at 7 a.m. and was conducted by about 200 immigration agents, said Robert Rutt, special agent in charge of the Office of Investigations for Immigration and Customs Enforcement in Houston.

It was part of more than a yearlong investigation by the agency that was prompted by accusations that Action Rags had hired illegal immigrants, Mr. Rutt said.

In addition to the 160 arrested, the plant’s employees included 2 United States citizens and 13 to 19 legal residents, Mr. Rutt said. They were released.

The company’s hiring practices are being investigated for potential criminal violations, Mr. Rutt said.

“By attacking this issue in a comprehensive, strategic way, we believe we can force the culture of corporations to change,” Mr. Rutt said.

William F. Estes, who identified himself as a lawyer for Action Rags, said the company was shocked by the raid.

“We want to abide by the law, and we’re going to abide by the law,” Mr. Estes said. “If we have an illegal employee, we don’t know it. No way. Tell us what the law is, and we’ll obey it.”

After the white immigration vans had driven away, Maria Lopez huddled across the street from the plant with friends. Four of her friends worked at the plant, Ms. Lopez said.

After one of them called, crying, at 7:20 a.m., she went to the plant, where family members and friends of other employees had gathered.

Ms. Lopez said her friends at the plant had lived in Houston for more than 10 years, but none were legal residents. She said she was worried that they would be deported.

“It’s not fair,” said Ms. Lopez, 27, a legal resident. “They’re working to support their families. This shouldn’t have happened.”