NEW HAVEN, Conn.  —  Five Spanish-speaking immigrants have filed a federal lawsuit challenging a requirement that workers only speak English on the job at a Deep River machine shop.

The five, who are in this country legally, have filed a discrimination suit against

GC Industries, a company that makes and finishes sheet metal.

At GC Industries a "Common Language Policy" posted on the bulletin board requires employees to speak English during work hours, except during breaks and lunch. The company notice cites safety, product quality and efficiency.

Policies dictating English in the workplace may be legal if a company can show a legitimate safety or business reason, according to the Equal Employment Opportunity Commission.