"I'd been drinking." / "I tested positive."

We are going to answer this one plainly, because it is a question people are too embarrassed to ask and the answer is often better than they expect.

Labor Code § 3600(a)(4) requires that the injury be "not caused by the intoxication, by alcohol or the unlawful use of a controlled substance, of the injured employee."

Read that carefully. The bar is causation, not presence.

And it is an affirmative defense — the employer has to prove it. You do not have to prove you were sober.

Why a positive test is not the end

Testing positive shows presence, not impairment, and not causation.

Cannabis metabolites in particular can remain detectable for weeks after any impairing effect has ended. A positive result days after the fact says nothing about the moment of injury.

And prescribed medication is not "unlawful use of a controlled substance." A worker taking a lawfully prescribed medication as directed is outside the statutory language — including medication prescribed for a previous industrial injury.

The employer still has to connect intoxication to the injury. Where the mechanism had nothing to do with impairment — a coworker's error, a defective machine, an unguarded hazard, being struck by someone else — causation fails even if the test was positive.

What actually matters

The mechanism. How did the injury happen, and could impairment plausibly have caused it?

Fault of others. If someone or something else caused it, intoxication did not.

The condition of the workplace. A missing guard, an unsafe procedure, or a known hazard is a competing cause with documentary support.

When and how the test was taken, what it measured, and its chain of custody.

And whether the employer applies this consistently, or only when there is a claim.

Two things this does not affect

Your medical treatment while the claim is investigated. Under § 5402(c), the employer must authorize up to $10,000 in treatment within one working day of the claim form, and that obligation is not suspended because there is a defense. More.

And the 90-day presumption still runs. If liability is not rejected within 90 days of the claim form, § 5402(b) presumes the injury compensable — and the presumption can only be rebutted by evidence discovered after the 90 days.

Be honest with your lawyer

Not with everyone. With your lawyer.

An attorney who knows about the test result on day one can address it. An attorney who learns about it from the defense at the deposition cannot.

And do not lie about it under oath. A defensible intoxication issue becomes a fatal credibility problem the moment it is denied and contradicted. More on testifying.