What type of testing is performed after a worker demonstrates behavior indicating possible substance abuse?

The correct answer is for-cause testing. This type of testing is specifically conducted when there are observable behaviors that raise concerns about a worker's potential substance abuse. These behaviors could include erratic actions, changes in mood or performance, or other indications that suggest the worker might be under the influence of substances.

For-cause testing is a proactive approach, allowing employers to address potentially unsafe situations in the workplace by assessing whether the individual is under the influence of drugs or alcohol. It serves to ensure the safety and productivity of the work environment by identifying issues promptly when signs of impairment are evident.

In contrast, other testing types mentioned in the options serve different purposes. Random testing involves unannounced screenings among a group without prior indications of substance abuse, while post-event testing typically occurs after an incident or accident, regardless of observed behaviors beforehand. Follow-up testing focuses on monitoring individuals who have previously tested positive to ensure compliance with recovery or rehabilitation programs. Each type has its specific applications, but for-cause testing directly relates to the immediate need to assess an individual's condition based on observed behavior.