You will need to consult a California-licensed attorney to parse and analyze the various legal issues here. For example, "intentional infliction of emotional distress" is a completely separate cause of action from breach of contract. I take it your question is whether you can recover damages for emotional distress in a breach of contract action. The answer, generally, is that such damages are only available 1) when the breach was made in "bad faith," AND 2) when a separate economic loss has resulted from the breach. See Maxwell v. Fire Insurance Exchange, 60 Cal. App. 4th 1446 (1998). Obviously, as an initial matter, you will need to examine your written contract (if any) with this employee to determine whether any provision was, in fact, breached. It is conceivable that your employee breached a provision of an oral contract, but a case premised on this will be an evidentiary nightmare.
Even if there is no written contract with the employee and/or or no provision on point, you may have a TORT (as opposed to contract-based) cause of action against the employee. At least one California appellate court has found that a managerial employee owes a so-called "fiduciary duty" to her employer; further, California law recognizes a "fiduciary-like" cause of action for breach of the duty of loyalty where an employee has taken action against her employer's best interest. See Diodes, Inc. v. Franzen, 260 Cal.App.2d 244 (1968); Stokes v. Dole Nut Co., 41 Cal.App.4th 285 (1995). One or both causes of action may be viable here, which is significant, because a California plaintiff MAY recover emotional distress damages caused by a breach of fiduciary duty. See Jahn v. Brickey, 168 Cal. App. 3d 399 (1985)
Since you mentioned "intentional infliction of emotional distress" in your question, I'll discuss it briefly. If you wish to pursue an IIED claim against your employee, you should be aware of the elements you will have to prove: "(1) EXTREME AND OUTRAGEOUS conduct by the defendant with the intent to cause, or reckless disregard for the probability of causing, emotional distress; (2) suffering of SEVERE OR EXTREME emotional distress by the plaintiff; and (3) the plaintiff's emotional distress is actually and proximately the result of defendant's outrageous conduct." Myung Chang v. Lederman, 172 Cal. App. 4th 67 (2009) (capitalization mine). As you can see, the courts have imposed a fairly high barrier to recovery for IIED, partly in recognition that many of our everyday actions cause emotional harm to others, but should not give rise to legal liability.
Finally, you might have a cause of action for the improper disclosure of "trade secrets," but be aware that the requirements for trade secret protection are quite stringent, and that this area of law is rather specialized. Again, you will have to consult a California-licensed attorney for a legal conclusion.
This answer does not constitute legal advice, and should not be relied on in place of a consultation with an attorney. No attorney-client, contractual, or fiduciary relationship has been formed as a result of this post or anyone's use of it. The only manner in which an attorney-client relationship can be formed with Charles Colman Law, PLLC, is via a countersigned letter of engagement on CCL letterhead. Charles Colman is only admitted to practice law in New York State, and before New York federal district courts. Although he endeavors to answer all Avvo questions knowledgeably, he cannot and does not provide any guarantees as to the thoroughness or accuracy of his responses.
You could sue anyone for anything, but I presume you mean successfully. Probably not. You need damages for any lawsuit, and your sleepless nights won't do it. And could you afford the litigation, and could the soon-to-be fired employee satisty any judgment you'd get against them? If you can't answer yes to both practical inquiries, there's not much point in considering a suit.
What about this information was "privileged," do you mean it was a trade secret? Has your business got a social media policy in effect that dictates what can and can't be posted on Facebook or other social network sites? Did the employee defame anyone, or were the email exhanges they exposed accurate?
See a business lawyer to discuss the details of your situation.
PLEASE READ THIS BEFORE YOU COMMENT, EMAIL ME OR PHONE ME. I'm only licensed in CA. This answer doesn't make me your lawyer, and neither do follow-up comments and/or emails and/or phone calls --- we need an actual agreement confirmed in writing before any attorney-client relationship is formed. Please don't expect me to respond to your follow-up queries. This answer doesn't constitute legal advice, and shouldn't be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
No, not really.
In California, the elements for intentional infliction of emotional distress (“IIED”) are as follows: (1) outrageous conduct by the defendant, (2) intention to cause or reckless disregard of the probability of causing emotional distress, (3) severe emotional suffering, and (4) actual and proximate causation of the emotional distress.
Conduct is extreme and outrageous when it exceeds all bounds of decency usually tolerated by a decent society, and is of a nature which is especially calculated to cause, and does cause, mental distress. Liability does not extend to mere insults, indignities, threats, annoyances, petty oppressions, or other trivialities. (Fisher v. San Pedro Peninsula Hospital (1989) 214 Cal.App.3d 590.)