Anger, gossip and irresponsibility are the sorts of behaviors that come to mind when we think about a toxic workplace, but a new study reveals another behavior leaders should beware of: rudeness.

Rude behavior is contagious and can spread quickly throughout the workplace, according to the study published in the Journal of Applied Psychology in June. The study found impolite interactions cause employees to perceive rudeness in later interactions, which often results in impolite retaliation.

Leaders shouldn’t tolerate this kind of harmful behavior — it’s not something that can be swept under the rug. Here are some ways to address rudeness in the workplace, before it spreads:

1. Set and maintain expectations.

One of the most important employee needs is clear expectations. If there aren’t any established boundaries and expectations, employees don’t have a guideline to follow.

“Great managers don’t just tell employees what’s expected of them and leave it at that; instead, they frequently talk with employees about their responsibilities and progress. They don’t save those critical conversations for once-a-year performance reviews,” states an article published in Gallup’s Business Journal in April.

Establish expectations through frequent conversations with employees. Don’t not just meet monthly or quarterly. Keep a positive tone and address examples of what employees already do well. When gray areas are uncovered, address them by collaborating with employees to determine a set rule.

Related: How the Epidemic of Bad Behavior Affects Your Business