A company can’t prohibit its workers from disclosing and discussing their salaries, according to a federal appeals court in New Orleans.

That’s because federal labor law says that employees always have a right to talk about the terms and conditions of their employment. And that’s true regardless of whether the employees belong to a union.

The case involved a non-union trucking company in Fort Worth, Texas that made its workers sign a confidentiality agreement. The agreement said that workers could not reveal any “financial information” or “personnel information” to anyone outside the company.

Although the agreement never specifically mentioned salaries, the court said it was nevertheless illegal because workers could reasonably assume that salary information was included.