What Is California Labor Code §4664: Prior Disability Awards?

(a) The employer shall only be liable for the percentage of permanent disability directly caused by the injury arising out of and occurring in the course of employment. (b) If the applicant has received a prior award of permanent disability, it shall be conclusively presumed that the prior permanent disability exists at the time of any subsequent industrial injury. This presumption is a presumption affecting the burden of proof.

What does Labor Code 4664 do?

Labor Code 4664 caps a California employer's permanent disability bill at the share the current injury actually caused, and treats an earlier award as proof that some disability already existed.

Section 4664 sits in the part of the Labor Code that sets disability payments. Subsection (a) states the main rule. The employer pays only for the percent of permanent disability (PD) the current injury caused. It does not pay for disability from another source.

Subsection (b) adds a rule for a worker hurt before. California calls that worker the applicant. If the applicant already has an earlier PD award, the law treats that old disability as still present at the time of the new injury. The statute calls this a burden-shifting presumption, not an automatic dollar cut by itself.

This rule reaches every California employer and insurer that owes permanent disability benefits. It comes up when a worker may have more than one source of harm to the same part of the body. That source can be an earlier work injury, an earlier settled claim, or another old award.

How does Labor Code 4664 change the dollar value of a PD award?

The employer's check covers only the share of the disability rating tied to the current injury, so a lower work-caused share means a smaller check.

Permanent disability pays by a rating, a percent set under Labor Code 4660.1 for injuries from 2013 on. That rating turns into weeks of pay under Labor Code 4658. Say a doctor rates a worker's spine at 30 percent disabled. The doctor then finds that 10 of those points trace to an old, unrelated condition. Under Labor Code 4664(a), the employer owes only for the 20 points the current injury caused. A doctor's written report has to support that split. A claims adjuster cannot just guess at it.

What does the prior-award presumption in subsection (b) mean?

If the worker already has a formal PD award for the same body part, the law presumes that old disability was still there when the new injury happened.

A prior award is a past, already-decided finding. It is not just an old complaint or an untreated condition. When one exists for the same body part, subsection (b) presumes the old disability was present. That presumption applies as of the date of the new injury. It can then support an apportionment finding under Labor Code 4663. Labor Code 4663 is the broader rule. It tells a doctor how to split disability between work and non-work causes. The statute calls this prior-award rule a conclusive presumption. It also calls the same rule a burden-shifting presumption. Those are two different legal ideas. The text does not fully explain how they fit together.

Why can't permanent disability awards add up to more than 100 percent?

Subsection (c) caps the lifetime total of PD awards for one body region at 100 percent, across seven listed regions.

Subsection (c)(1) sets a lifetime ceiling. All PD awards for one body region, added together, cannot pass 100 percent. The one exception is a condition conclusively presumed to be total under Section 4662. The statute lists the regions this cap applies to:

• Hearing
• Vision
• Mental and behavioral disorders
• The spine
• The upper extremities, including the shoulders
• The lower extremities, including the hip joints
• The head, face, cardiovascular system, respiratory system, and any other region not listed above

Subsection (c)(2) adds a related rule. When one accident hurts more than one body part, those separate ratings, added together, still cannot go over 100 percent.

How is Labor Code 4664 different from Labor Code 4663 apportionment?

Labor Code 4663 tells a doctor how to split disability between work and non-work causes. Labor Code 4664 sets what the employer owes after that split, plus the prior-award rule and the lifetime cap.

Labor Code 4663 is the broader rule. It reaches any non-work cause, from a car crash to ordinary aging. It also requires the worker to disclose any earlier permanent disabilities on request. Labor Code 4664 does two narrower jobs. Subsection (a) states the employer's resulting bill in plain terms. Subsections (b) and (c) handle a documented prior PD award tied to that body region. A worker can face both sections in one claim. Section 4663 covers the medical split. Section 4664 covers the prior-award presumption and the lifetime cap.

What should I save if an old injury might affect my case?

Keep records of any earlier workers' comp claims to the same part of the body, and ask the evaluating doctor to address Labor Code 4664 in writing.

Save the paperwork from any earlier claim or settlement for the same body part. Keep the final award too. When you see a Qualified Medical Evaluator (QME) or an Agreed Medical Evaluator (AME), ask the doctor to address Labor Code 4664 in writing. The report should state what share the current injury caused. It should also explain how any old award factored into that number. A report that skips this analysis can be sent back.

An insurer may point to an old injury or an earlier award to lower what it owes you. If that happens, ask for the full medical report in writing. Ask for the apportionment analysis too. Gather copies of any earlier workers' comp awards or settlements tied to that body part. A workers' compensation attorney can check whether the Labor Code 4664 presumption was applied correctly. The attorney can also check whether any apportionment finding is backed by the medical record. The firm reviews each matter individually. Call (661) 273-1780 or use the contact form to ask about your claim.