A group of Hispanic workers is suing a Michigan industrial plant that fired them for taking part in the Day Without Immigrants protest in February.

The Detroit Free Press newspaper reports the workers have taken their case to the National Labor Relations Board in Washington.

Their lawyer, Tony Paris, tells the newspaper the company discriminated against them because they are Hispanic immigrants who took part in a political protest.

Paris says EZ Industrial Solutions questioned about 20 workers about whether they planned to take part in the nationwide protest. The plant allegedly threatened to suspend any worker for one week if he marched.

Paris says instead of a weeklong layoff, the workers were fired and the company threatened to report them to immigration authorities.

One of the affected employees says those who work at EZ have an "informal schedule." She says they stayed home for as much as three days at a time without penalty or being made to justify the absence.

In a message sent to the Detroit Free Press, an official with the EZ Industrial Solutions said the law is clear that someone cannot simply fail to show up on the job and take part in a nonwork-related political protest without consequences.

He said he is confident the lawsuit will be dropped.