"They're making me take a drug test."

What the statute actually requires

§ 3600(a)(4) excludes compensability where the injury is caused by the employee's intoxication by alcohol or the unlawful use of a controlled substance.

Read the words. Not "where a test was positive." Not "where the employee had used something." Caused by.

The burden is on the employer, and it is an affirmative defense they have to establish — against the backdrop of Labor Code § 3202, which requires the workers' compensation statutes to be liberally construed in favor of extending benefits.

Why positive tests often fail to defeat claims

Cannabis is the clearest example. THC metabolites are detectable for days to weeks after use. A positive cannabis test tells you almost nothing about impairment at the moment of injury — and California law now generally restricts employers from acting on non-psychoactive metabolite testing in the employment context, which reflects that same scientific reality.

Prescription medication is not unlawful use. If you were taking something as prescribed, § 3600(a)(4) does not reach it — including medication prescribed for a prior work injury.

And causation still has to connect. A scaffold that collapsed, a machine that lacked a guard, a driver who ran a light — the mechanism of injury frequently has nothing to do with the worker's condition, and the employer has to bridge that gap with evidence, not inference.

What to do

Don't refuse without thinking about it. Refusing can carry employment consequences separate from the comp claim, and an adverse inference is possible. That is a real cost.

Tell them, in writing, about every prescription you take — before the test if you can, and to the collector at the time. This is the single most useful thing you can do, and it is the thing people forget.

Ask what is being tested and by what method. Note the time of the test relative to the injury. A test taken eleven hours later, after you were driven to a clinic, is a weaker piece of evidence than one taken at the scene, and the gap matters.

Keep your own record of the timeline — when the injury happened, when you reported it, when you were sent, when the sample was taken.

And keep reporting and filing. The claim goes forward regardless. A test result is a defense they may raise, not a bar on filing. My employer says I can't file.