If you have an Ethics #Hotline, and even if you don't, sooner or later you will get an employee complaint alleging that they are working in a "hostile work environment."
Such claims are often based on rude, crass, annoying, or belittling workplace behavior by one employee against another. The complainants are often times rightly upset, and their claims should be taken seriously and properly investigated. You don't want employees being mean to each other, or to have unhappy employees.
But, it's important to understand that the term "hostile work environment" is a term of art in employment law. In a nutshell, a "hostile work environment" is harassing behavior based on a protected class that is prohibited by Title VII of the Civil Rights Act of 1964 (and similar state laws). It is one of the two types of harassment generally prohibited by Title VII, the other being quid pro quo harassment.
Both hostile work environment and quid pro quo harassment are most often based on alleged sexual harassment, though they both could be based on any protected category.
To be successful in a hostile work environment claim, an employee must show unwelcome conduct, based on their protected class, that is attributable to the employer and is severe or pervasive.
A plaintiff must prove all of these elements. So, for example, if the other elements are met, but the incident in question was a one-time thing, often times a court will hold that the claim fails the "severe and pervasive" test. There have been cases, however, where the actions were so egregious that one time was enough.
Another example of a claim that has failed is when the plaintiff alleged that she was subject to harassment "as a female" rather than "because she was female." The employee there didn't demonstrate that the harassment was based on her protected class.
And so on and so forth - there are a huge number of cases out there on every aspect of these elements, from whether or not the conduct was "unwelcome" to whether the employer knew about the conduct and failed to take action. Yet another reason to have a formalized reporting/complaint procedure!
According to the EEOC, legally prohibited harassment must create a work environment that would be intimidating, hostile, or offensive to reasonable people, and may include offensive jokes, slurs, epithets or name calling, physical assaults or threats, intimidation, ridicule or mockery, insults or put-downs, offensive objects or pictures, and interference with work performance. Again - assuming all the elements above are met.
The takeaway: Don't correct or challenge your employee when they allege a "hostile work environment" when what they really mean is that they are working with people that are being hostile to them. That's not going to make them feel better or solve anything.
But, you should know for yourself whether you have a potential Title VII hostile work environment claim on your hands for a variety of reasons such as letting insurance carriers know, for tracking purposes, and holding your managers accountable.