Once again federal agents have conducted a large workplace raid — this time at a manufacturing plant in south Mississippi.

After sealing off entrances Monday at the Laurel, Miss., plant which makes electrical transformers and several other products, agents identified 595 people as illegal immigrants.

A tip from a union member sparked a three-year investigation into Howard Industries, according to the U.S. Immigration and Customs Enforcement. So many workers were detained that the plant was shut down for a day. This action was prompted by charges that companies in southern Mississippi hire illegal immigrants.

Robert Shaffer, head of the Mississippi AFL-CIO, said: "Jackson, Hattiesburg, Laurel and all areas along the coast, it's a little Mexico. I'm not against people trying to make a living. I have a compassion for those folks. But at the same time, the taxpayers of Mississippi shouldn't be subsidizing a plant that won't even hire their own workers."

Howard Industries has benefited from a $31.5 million, taxpayer-backed incentive plan for the plant to expand. The company issued a statement that it "runs every check allowed to ascertain the immigration status of all applicants for its jobs. It is company policy that it hires only U.S. citizens and legal immigrants."

Yet there were tensions between union workers and immigrants regarding overtime and promotions.

The Associated Press reported from Laurel: "The raid created hysteria among many in the Hispanic community here. Rumors that federal agents would begin going house-to-house prompted some families to seek refuge at Iglesia Cristiana Penial, a church with a largely Hispanic congregation."

This is becoming a common occurrence. On May 12, federal immigration officials raided Agriprocessors, the nation's largest kosher meatpacking plant, in Iowa. Nearly 400 workers were detained and dozens of fraudulent permanent resident alien cards were seized from the plant's human resources department, according to court records.

The raids and disruptions they cause in immigrant families and communities show how badly comprehensive immigration reform is needed.