Aggravation Rule Law and Legal Definition

The aggravation rule is a doctrine of general workers' compensation law which provides that, where an employment injury worsens or combines with a preexisting impairment to produce a disability greater than that which would have resulted from the employment injury alone, the entire resulting disability is compensable. In short an employer is liable under the aggravation rule when an employment injury creates, worsens, or combines with a preexisting condition to create a new and greater disability. Where the preexisting impairment results from an injury which occurred during the course of employment with a prior employer, a second or final employer is liable under the aggravation rule for the entire cost of an employee's disability if the preexisting impairment was aggravated during the course of the employee's second or final employment. On the other hand, a first employer is liable if the employee's ultimate medical condition arises from the "natural progression" of an injury that occurred during the course of the employee's first employment.

The following are examples of case law discussing the rule:

An employer is liable for employment conditions that cause an injury or aggravate or accelerate a pre-existing condition under the aggravation rule, which dictates that the employer takes the employee as he finds him. [Haw. Stevedores, Inc. v. Ogawa, 608 F.3d 642 (9th Cir. 2010)]

Traditional workers' compensation regimes follow the aggravation rule, which makes an employer liable for an employee's entire disability even though the disability resulted from a current employment injury and a preexisting impairment. However, § 8(f) of the Longshore and Harbor Workers' Compensation Act, 33 U.S.C.S. § 908(f), limits the employer's liability for a work-related permanent disability if the employer can show that the employee had a preexisting permanent partial disability that contributed to the current employment-related disability. After 104 weeks, § 8(f) shifts liability from the employer to a special fund financed through contributions from employers in the industry. 33 U.S.C.S. §§ 908(f)(1), 944.[Chevron USA, Inc. v. Heavin, 204 Fed. Appx. 361 (5th Cir. 2006)]

The aggravation rule, which is a doctrine of general workers' compensation law, is often known as the "last employer rule," although the two terms are probably not precisely interchangeable; rather, it may be more correct to say that the aggravation rule is the "two-injury branch" of the last employer rule. [Operators & Consulting Servs. v. Dir., OWCP, 170 Fed. Appx. 931 (5th Cir. 2006)]