Rising Impact of Cumulative Trauma Claims in California Workers’ Compensation System

Author, Jadyn Brandt, Client Communications Coordinator, Rancho Mesa Insurance Services, Inc.

Claims involving Cumulative Trauma (CT) injuries are growing significantly, across California.

Data collected by the Worker’s Compensation Insurance Rating Bureau (WCIRB) shows growth of these types of claims accelerated in 2022, 2023 and 2024. The WCIRB now estimates that more than 25% of indemnity claims involve CT.

The Los Angeles area continues to see the largest concentration of CT claims; however, the recent increases have been observed state-wide.

Most CT claims are filed after an employee is terminated. Based on WCIRB claim survey data, approximately 60% of recent CT claims were filed post-termination, that’s an increase from prior studies which indicated only 40% of CT claims were filed post-term.

The rise in claims involving CT is having real effects on costs to employers, and underwriting losses.

The WCIRB reports combined ratios have exceeded 100% for the last six years and have been above 125% for the last two years. In accident year 2025, higher claim frequency, rising average medical costs, and increasing average allocated loss adjustment expenses (ALAE), led to a combined ratio of 129%, marking the highest ratio in over 15 years.

Rancho Mesa is seeking to reform California’s CT claims situation by drafting and sending letters to legislators asking for reform. If you are interested in taking action, templates are available addressed to California Senator Lola Smallwood-Cuevas and California Assembly Member Lisa Calderon at both their regional and capitol offices.

Cumulative Trauma Injuries: What They Are and How to Combat Them

Author, Jadyn Brandt, Client Communications Coordinator, Rancho Mesa Insurance Services, Inc.

Cumulative Trauma injuries are on the rise in California, and employers should be aware of the consequences of these costly claims.

Cumulative Trauma encompasses work-related injuries or diseases that develop over time from repetitive physical or mental stress. These are injuries that occur over time, not on a specific date; things like chronic back or knee pain, carpal tunnel, or hearing loss. Because these claims take place over a long period of time, it is more difficult for an employer to defend themselves against CT claims than against specific injury claims.

The Workers’ Compensation Insurance Rating Bureau (WCIRB) reports that CT claims now make up 3% of all claims, and the number of CT claims has doubled over the past 10 years. Additionally, 39% of CT claims are filed post-termination.

Because CT injuries compound over time, it is important for employers to take regular precautions against possible employee injuries.

Encourage Employee Reporting

Early reporting of unsafe conditions is an important step in preventing injury. Employers should encourage employees to report and document potential safety hazards on the job. Improper use of equipment while tree trimming, a lack of PPE on a construction site, or a need for ergonomic changes in the office are all risks employers should be aware of, and employees should feel comfortable reporting.

Rancho Mesa clients can use Observation Reports in the SafetyOne™ platform to document hazards that need to be addressed.

Proper Safety Training

Training employees in proper safety techniques is also an important step in preventing both immediate injury and CT claims. Employees should be aware of how to properly use all equipment and protect their bodies from repetitive stress.

For employees in construction and landscape industries whose jobs require manual labor, Rancho Mesa’s RM365 Advantage Mobility & Stretch™ Program helps workers prepare themselves for strenuous physical tasks and prevent injury.

Office employees can also benefit from ergonomic training to help prevent aches and pains associated with sedentary work. Office Ergonomics and Industrial Ergonomics training courses are both available through Rancho Mesa’s RM365 HRAdvantage™ portal.

For a closer look at the effects of CT claims and how to best combat them, join us for our Cumulative Trauma Claims: Trends, Impact & Best Practices workshop, happening on Friday, January 30, at 9 a.m.