First responders in West, Texas*. Sales clerks in the stores near the finish line at the Boston Marathon. Staff of the District Attorney's office in Kaufman County, Texas. Teachers and administration at Sandy Hook Elementary. Ticket-takers and popcorn-scoopers at the Century 16 movie theater in Aurora, Colorado.

*Although the explosion at West Fertilizer Company appears to have been an industrial accident, as of this morning, law enforcement authorities have not ruled out the possibility of a crime or terrorist act.

Prayers for all those who were killed, injured, or are grieving as a result of these terrible acts.

Employers, do you have a workplace violence plan in place? Of course, it may not stop a terrorist, but it should prevent some incidents and save lives in the event of a crisis. Here is what it should contain at a minimum:

1. A ban on fighting or other violent behavior of any kind, as well as threatening, "bullying," intimidating, or abusive behavior.
2. A ban on weapons in the workplace.
3. A way for employees to report suspicious activity, behavior, or concerns.
4. The strongest substance abuse provisions that your state's laws will allow.
5. An employee assistance program so that your employees with mental illness or personal problems can get help early. (In most jurisdictions, an EAP isn't mandatory, but it is a very good idea.)
6. A preliminary plan to follow in the event of an incident (realizing that flexibility will be needed, depending on the circumstances), and a designated person or team who will coordinate evacuation efforts and contacts with law enforcement.

In addition, and with all due respect to the U.S. Equal Employment Opportunity Commission, which doesn't want employers to do much in the way of criminal background screening, DO screen job applicants or offerees for criminal convictions. You can still address each conviction on a case-by-case basis, but don't be afraid to reject a candidate with a history of violent crime.

Some time ago, I did a presentation with a psychiatrist on preventing workplace violence. We didn't talk about terrorism but did talk about more "garden-variety" types of violence in the workplace, such as "going postal" or domestic violence that carries over into the work environment.

According to the psychiatrist, an individual who may be prone to violence often has one or more of the following characteristics:

• A personality disorder (narcissistic or antisocial)
• Substance abuse
• Personal or financial distress
• Possibly, a physical or mental illness other than a personality disorder
• A history of poor impulse control
• A history of violence

Some warning signs that you and your employees can be trained to look for:

• Complaints about unfair treatment that cannot be verified
• Preoccupation with military and weapons
• Outbursts of temper
• Inability to tolerate criticism
• Irrational or delusional thinking
• Demanding or controlling demeanor

As any employer knows, there are federal and state laws making it more difficult to take effective steps in dealing with an employee who appears to be a threat. Probably the most significant limitation that applies to most employers is the Americans with Disabilities Act. Even so, a safe workplace is an "essential function of the job," and you have a right to take reasonable measures to ensure that your employees are safe.

Here are some effective crisis prevention steps that should not create a problem under the ADA:

• Take all threats seriously.
• Quickly work to defuse workplace conflicts, including harassment or bullying situations. Recognize that sometimes the violent employee may have first been a victim of harassment or bullying.
• Consider consultation with an occupational psychiatrist or psychologist. NOTE: By doing so, you may lose a defense to an ADA claim that you were unaware that the individual had a disability, but in a violence scenario, that's a relatively small sacrifice to make -- also, you'll still have other ADA defenses. The medical professional can (1) help you determine whether the threat is real, (2) help you address any conditions in the workplace that may be aggravating the situation, (3) help assess issues in the life of the individual making the threats, and (4) advise you on the most effective/least harmful way to involve law enforcement.
• Consult with legal counsel as well, as needed, to avoid creating ADA or other legal issues that you might not be able to defend.

Next week, I'll post on some of the psychiatrist's recommendations on how to deal with an "at-risk" employee.

BREAKING: One of the suspects in the Boston Marathon shooting (the one in the black cap) was killed last night in a shootout with the police; the other is still at large. A campus police officer at Massachusetts Institute of Technology was also killed.