In 2014, California passed AB 2053
which included the following language, now codified into law:
"For purposes of this section, "abusive conduct" means conduct of an employer or employee in the workplace, with malice, that a reasonable person would find hostile, offensive, and unrelated to an employer's legitimate business interests. Abusive conduct may include repeated infliction of verbal abuse, such as the use of derogatory remarks, insults, and epithets, verbal or physical conduct that a reasonable person would find threatening, intimidating, or humiliating, or the gratuitous sabotage or undermining of a person's work performance. A single act shall not constitute abusive conduct, unless especially severe or egregious."
Since this language is now codified into law, there may be legal recourse using this language. To our knowledge, it has not been tested in the court that we know of, YET being the key word. We suggest you consult with an employment law attorney to get a legal opinion about this idea.
To read about Nationwide progress with the Healthy Workplace Bill: