Workplace violence is generally classified into four primary types, as defined by OSHA under the General Duty Clause. Each type is categorized by the source of the threat, not by the severity of the incident. Understanding these categories is essential for building an effective workplace violence prevention program.
The four types of workplace violence are:
- Criminal intent
- Customer or client violence
- Worker-on-worker violence
- Intimate partner violence
There is also increasing discussion around a fifth, emerging category related to terror or extremist-driven violence, which organizations should understand within the broader framework.

The Four OSHA-Recognized Types of Workplace Violence
Type 1: Criminal Intent
Type 1 involves individuals who have no legitimate relationship with the organization. The violence occurs during or as a result of criminal activity such as robbery, theft, or trespassing.
This category often includes incidents committed by outsiders who target a workplace because of perceived opportunity, access, or vulnerability.
Type 2: Customer or Client Violence
Type 2 comes from individuals who have a business relationship with the organization but are not employees. This can include customers, clients, patients, passengers, or vendors.
These incidents often stem from frustration, conflict, unmet expectations, or emotionally charged interactions tied to service delivery.
Type 3: Worker-on-Worker Violence
Type 3 originates within the organization. It includes acts of violence between employees, supervisors, or managers.
This category covers a wide range of behaviors, from escalating conflict to targeted acts driven by grievances, interpersonal disputes, or organizational stressors.
Type 4: Intimate Partner Violence
Type 4 involves violence that stems from a personal relationship outside the workplace but spills into the work environment. This typically includes current or former spouses, dating partners, or family members of an employee.
Although the aggressor does not work for the organization, the workplace can become a point of access, making this one of the most commonly overlooked yet significant risk areas.
Is There a Fifth Type of Workplace Violence?
While OSHA formally recognizes four types, arguably a fifth category related to terrorism or extremist-driven violence.
This type often overlaps with criminal intent but is distinct in motivation. These incidents are driven by ideological, political, or extremist goals and may intentionally target workplaces as symbols or gathering points. Past attacks, such as the 2015 San Bernardino incident, illustrate how terror-motivated violence can intersect with workplace settings.
Although not a standalone OSHA category, organizations should consider this risk when evaluating overall threat exposure under the General Duty Clause.
Why Understanding These Types Matters for Prevention
Each type of workplace violence originates from a different source, which means prevention strategies cannot be one-size-fits-all.
When organizations understand where violence is most likely to come from, they can:
- Identify gaps in policy and training
- Design targeted prevention measures
- Recognize early warning signs
- Address overlooked risks, especially intimate partner violence
Effective workplace violence prevention programs are built by evaluating whether policies, procedures, and reporting mechanisms address each potential source, not just the most obvious ones.
Applying the Framework
In the video “The Four Types of Workplace Violence,” I explain how this framework helps organizations identify risk before incidents escalate. By understanding how OSHA defines workplace violence and where threats commonly originate, leaders can take a more proactive and comprehensive approach to safety.
This framework is not about predicting specific incidents. It is about building awareness, preparedness, and resilience across the organization.
Sources
- OSHA’s overview of workplace violence under its enforcement and guidance framework: https://www.osha.gov/workplace-violence/enforcement OSHA
- OSHA’s general definition of workplace violence and hazards: https://www.osha.gov/workplace-violence OSHA
- NIOSH (CDC) classification of the four types of workplace violence: https://wwwn.cdc.gov/WPVHC/Nurses/Course/Slide/Unit1_5 CDC
- OSHA and NIOSH definitions of workplace violence categories and examples: https://www.osha.gov/sites/default/files/enforcement/directives/CPL_02-01-058.pdf
- OSHA
Additional Useful References
- OSHA workplace violence prevention guidance (PDF): https://www.osha.gov/sites/default/files/publications/osha3148.pdf
- OSHA
- State-level workplace violence FAQs and categories (California DOSH): https://www.dir.ca.gov/dosh/Workplace-Violence/FAQ.html
- CalDIR
Context and Definitions (for deeper grounding)
- OSHA’s General Duty Clause related to workplace safety requirements: https://en.wikipedia.org/wiki/General_duty_clause
- Wikipedia
- Workplace violence defined in broad occupational safety context (NIOSH/CDC): https://www.cdc.gov/niosh/learning/safetyculturehc/module-2/10.html cdc.gov
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