Reasonable suspicion Definition

Historical Context and Why It Matters

The concept of reasonable suspicion originated in U.S. constitutional law (Terry v. Ohio, 1968), describing when authorities could lawfully investigate based on observable evidence. In workplace compliance, it evolved under the Drug-Free Workplace Act of 1988, mandating that organizations act on credible suspicion of substance use in safety-sensitive positions. Today, this standard extends beyond drug or alcohol cases to include data misuse, ethical breaches, and workplace safety violations.

Employers must balance due process and safety—acting promptly when risk indicators arise, but always based on documented, verifiable observations. For HR Managers, Compliance Officers, and People Leaders, reasonable suspicion provides the structure to intervene responsibly, mitigate risk, and preserve trust.

Recognizing Reasonable Suspicion at Work

• Impairment Indicators: Slurred speech, poor coordination, or erratic movements observed by more than one supervisor.
• Behavioral Changes: Sudden mood swings, withdrawal, or aggression that affect workplace harmony or safety.
• Performance Decline: Noticeable drop in productivity, unexplained absences, or missed deadlines following a pattern.
• Physical Evidence: Smell of alcohol, possession of paraphernalia, or uncharacteristic appearance changes.

These signs must always be documented with specifics—time, date, observed behavior—and verified when possible. Training managers through Emtrain’s Drug and Alcohol Awareness Training ensures observations are handled lawfully and without prejudice.

The 10-Factor Reasonable Suspicion Test

To determine reasonable suspicion, consider the following 10 factors along with other relevant information, while taking into account the employee’s explanation for their behavior:

1. Physical Symptoms: Altered or slurred speech, incoherent statements, dilated or constricted pupils, flushed skin, excessive sweating, or unexplained drowsiness or loss of consciousness.
2. Behavioral Changes: Unexplained, abrupt, or radical shifts in behavior such as violent outbursts, hyperactivity, or mood swings.
3. Motor Skill Impairment: Inability to walk steadily or perform normal manual tasks essential to job functions without explanation.
4. Frequent Disappearances: Unexplained absences or prolonged disappearances from the work area.
5. Accidents or Near-Misses: Workplace incidents or near-accidents that appear linked to sensory or motor skill malfunctions.
6. Odor of Alcohol: Detectable smell of alcohol on an employee during work hours.
7. Direct Observation: Witnessing the employee using or possessing drugs or alcohol on duty.
8. Criminal Investigation: The employee is identified as the subject of a criminal investigation involving illegal drug use, possession, or distribution.
9. Test Tampering Evidence: Any indication that the employee has tampered with or attempted to falsify a previous drug test.
10. Credible Report: A report of reasonable suspicion provided by a reliable and credible source.

This 10-factor test helps HR and Compliance leaders ensure fair, consistent, and objective evaluation when assessing potential substance-related concerns.

How HR and Compliance Leaders Should Act on Reasonable Suspicion

1. Document Objectively: Record behaviors without assumptions. Avoid subjective language like “seemed intoxicated”; instead note, “stumbled when walking” or “smelled strongly of alcohol.”
2. Follow Policy: Refer to the organization’s written Workplace Safety Training and drug-free policy for next steps.
3. Engage HR Immediately: Managers should not confront employees alone. HR ensures consistency and confidentiality.
4. Maintain Confidentiality: Investigations must be discreet, protecting employee dignity.
5. Take Corrective or Protective Action: Depending on the situation, this may involve testing, temporary reassignment, or removal from duty.

A structured response process protects all parties and ensures compliance with state and federal standards, including OSHA safety requirements.

Implementing a Legally Sound Reasonable Suspicion Policy

Effective implementation of a reasonable suspicion program relies on clarity, consistency, and training. Organizations should:

• Align Policies with Law: Integrate OSHA and ADA standards to ensure that suspicion-based action doesn’t conflict with disability protections. Learn more in Emtrain’s Disability Protections (ADA) Training.
• Ensure Equal Enforcement:
  Incorporate your organization’s EEO Policy Template to guarantee consistent and non-discriminatory application of reasonable suspicion procedures. An EEO-aligned policy ensures that investigations are conducted fairly across all employee groups, mitigating bias and supporting compliance with Title VII and EEOC guidelines.
• Train Supervisors: Equip managers to recognize and document behavior objectively, not subjectively.
• Avoid Bias: Base all suspicion on factual evidence—not appearance, identity, or stereotype.
• Update Policies Regularly: Reflect current legislation, including state-level substance testing laws.
• Provide Access to Experts: Use confidential guidance features like Emtrain’s Ask the Expert to handle complex or sensitive cases.

Real-World Examples: Applying Reasonable Suspicion

• Example 1: A construction foreman observes an equipment operator showing signs of imbalance and delayed responses. After documentation and HR consultation, testing confirms alcohol use—preventing potential injury and demonstrating due diligence.
• Example 2: A call center manager notices an employee frequently accessing sensitive databases outside of assigned duties. A structured review identifies a potential data breach. Following reasonable suspicion standards ensures a fair, compliant investigation.
• Example 3: A retail supervisor records multiple incidents of erratic customer interactions by an employee. A documented pattern of concern justifies HR intervention under the company’s drug-free policy.

Each scenario underscores that reasonable suspicion is not about accusation—it’s about safety, consistency, and fairness.

Supporting Resources

• U.S. Department of Labor – Drug-Free Workplace Policy Builder
• National Institute on Drug Abuse – Workplace Prevention Programs

These resources outline federal standards and practical steps for implementing compliant and humane workplace substance policies.

Final Thoughts

Reasonable suspicion is the cornerstone of ethical and compliant workplace oversight. It enables leaders to act responsibly, protect employee wellbeing, and maintain legal integrity. For HR Managers, it mitigates exposure and promotes accountability; for Compliance Officers, it ensures documentation and fairness; and for People Leaders, it strengthens culture and trust.

Emtrain’s comprehensive learning ecosystem—including  Drug and Alcohol Awareness Training, Workplace Safety Training, and Disability Protections (ADA) Training—empowers organizations to act decisively and compliantly when reasonable suspicion arises.

Video Preview: Warning Signs and Red Flags

In this brief video scenario, an employee shares a real workplace encounter that highlights the importance of recognizing red flags:

A woman arrived at the front desk claiming to be selling something for the business owner but had no business card or identification. When informed that the owner was unavailable, she became agitated, accusing the front desk manager of lying and declaring, “They can’t make me leave.” Her erratic behavior made staff uncomfortable, prompting an employee to call security.

This incident demonstrates how emotional instability, aggressive speech, and refusal to comply with workplace boundaries can serve as warning signs of potential risk. Recognizing and responding appropriately to these behaviors protects employees and maintains a safe, professional environment.