Do you have clear policies to deal with incidents of workplace violence within your company? Is everybody in your company aware of them?

Two shocking recent tragedies — one in Kansas and the other in Florida — resulting in a total of five green industry employees being shot and killed have brought workplace violence into the industry’s living room. That something so tragic happened not just once, but twice, means it can happen again.

Read more: We Must Address Workplace Violance — STAT

Seeking clues as to why nearly two million workers report having been victims of workplace violence annually (including 403 workplace homicides in 2014), I spent a recent afternoon learning what I could about the subject. While I encountered an incredible amount of information, the six violence prevention suggestions shared by a Rutgers University site offered a great starting point for any business owner wanting some insight into the chance of something like this happening in his or her company.

  1. Have close contact with employees. Make sure that everyone feels part of the organization.
  2. Review each and every act of violence that has occurred in the workplace, even if it may be considered minor.
  3. Have a written policy explaining how violence in the workplace will not be tolerated.
  4. State clearly what workplace violence is and what is and is not acceptable behavior.
  5. Train all staff about the “buddy” system so each employee has someone to go to in case they are having problems at work.
  6. Remain calm when confronting an employee.

You may think that spring, given how much work must get done, is just too darn busy to consider the possibility of violence happening in your operation, never mind stopping to discuss the matter with your team and enunciating a clear prevention plan. After all, you’re working 50 to 60 hours a week and your employees are putting in long, tough days out in the weather.

Consider, though, that these are just the type of conditions when nerves can fray, resentment can begin to set in and tempers can flare.

You owe it to yourself and especially the other people within your company to make it very clear where you stand on workplace violence: It won’t be tolerated under any circumstances.

Warning Signs

While the great majority of employees with grievances don’t become violent, some sort of “trigger” may push an already vulnerable person to take drastic action.

Be wary of employees who start to behave in the ways listed below:

  • They say they’ve been treated unfairly.
  • They say they’re being forced to wait for something (a promotion, raise, etc.).
  • They show signs of mental instability.
  • They begin to isolate themselves or are thought of as “loners.”
  • They have recently been disciplined for something.

It’s also important to be aware of the traits most often found in violent employees: history of violent behavior resulting in involvement with the criminal justice system, bitter and unhappy, no job security, upset with low-level tasks to do and substance abuse (including taking heavy medications).