On the afternoon of Tuesday, April 15, 2026, a tunnel collapse at an active construction site near Knights Ferry claimed the life of a 35-year-old Coulterville woman and sent a second worker to the hospital. The fatal workplace accident unfolded at the Canyon Tunnel Project worksite, a major infrastructure initiative in Calaveras County, and drew a massive emergency response that lasted well into the night.
She was working inside the Canyon Tunnel Project when a partial collapse trapped her approximately 200 feet into the tunnel, leaving rescue crews racing against time in what would become an hours-long technical rescue operation. Despite the extraordinary efforts of more than 30 firefighters from multiple agencies, the woman did not survive. Her death is a stark reminder of the dangers that underground construction workers face every day on the job.
What Happened at the Knights Ferry Tunnel Collapse
At approximately 3:42 p.m., the Modesto Fire Department and Stanislaus Consolidated Fire Protection District were dispatched to a reported rescue incident near the intersection of Schell Road and Sonora Road, outside the community of Knights Ferry.
Firefighters and an ambulance crew arrived at the tunneling project to find that a collapse had occurred. One injured person had already exited the tunnel when firefighters arrived and was transported to a local hospital with minor to moderate injuries. A second worker, later identified as Twyla Capurro, remained trapped inside the partially collapsed tunnel.
The collapse happened approximately 200 feet into the tunnel. Despite an extended rescue effort involving dozens of emergency personnel, Capurro was confirmed dead, and her body was recovered from the tunnel at approximately 10:04 PM. All emergency personnel cleared the scene at approximately 11:00 PM.
About the Canyon Tunnel Project
The Canyon Tunnel Project is a worksite located at 16940 Schell Road. The project is a joint effort between the Oakdale Irrigation District and the South San Joaquin Irrigation District. According to reporting in Smart Water Magazine, the $84 million project is described as an ambitious initiative to protect and modernize water delivery for thousands of Central Valley residents and farmers.
Last July, the South San Joaquin Irrigation District awarded the construction contract to Drill Tech Drilling & Shoring, an Antioch-based firm with significant experience in complex tunneling and infrastructure work. The ceremonial groundbreaking took place on August 4 near Goodwin Dam on the Stanislaus River northeast of Knights Ferry. The 12,000-foot tunnel is designed to bypass a vulnerable section of the century-old Joint Supply Canal, which has been increasingly threatened by landslides.
Following the collapse, the South San Joaquin Irrigation District stated that all work on the project has been suspended. At the time of the collapse, the project appeared to be progressing on schedule. In fact, the South San Joaquin Irrigation District had posted a Spring 2026 update video to YouTube just hours before the accident, showing tunneling work actively underway inside. That footage now stands as a sobering contrast to what unfolded later that afternoon, raising serious questions about the conditions under which workers were operating and whether all appropriate safety protocols were in place at the time of the collapse.
The Emergency Response
The initial call was quickly escalated. The Modesto Fire Department and Stanislaus Consolidated Fire Protection District responded first, but the rescue call was upgraded to a technical rescue requiring additional crews and specialized equipment. The Turlock Fire Department also responded to assist.
A unified command was established involving Copperopolis Fire, Modesto Fire Department, Stanislaus Consolidated Fire Protection District, and the Calaveras County Sheriff’s Department. Drone operations were deployed inside the tunnel to assess conditions and support rescue efforts. More than 30 firefighters responded, using three engines, two truck companies, one rescue unit, one squad, and multiple utility vehicles.
The scale of the response reflected just how dangerous and complex the rescue operation was. Tunneling collapses present unique challenges for emergency crews, including unstable ground conditions, limited access points, poor air quality, and the constant risk of secondary collapse. The deployment of drones inside the tunnel was a critical step.
These provide incident commanders with real-time visual information about conditions deep within the structure without requiring additional personnel to enter an unsafe environment. Despite every resource available being brought to bear, the effort to reach the victim alive was ultimately unsuccessful. Her body was recovered from the tunnel at approximately 10:04 PM, more than six hours after the initial collapse was reported.
California Workers’ Compensation Death Benefits
When a worker is killed in a job-related accident, California law provides a path for surviving family members to seek financial support. Workers’ compensation death benefits are available to dependents of workers who die as a direct result of a work-related injury or illness under California Labor Code Section 4700.
Eligible survivors may include spouses, registered domestic partners, minor children, and other individuals who were financially dependent on the deceased worker. The level of dependency, whether total or partial, affects the amount of benefits available.
Under California Labor Code Section 4702, death benefits are paid in installments to total dependents and vary based on the number of dependents. In addition to ongoing payments, Labor Code Section 4701 provides for a burial expense allowance. Dependents have one year from the date of death, or one year from the last payment of workers’ compensation benefits, to file a claim, per Labor Code Section 5406.
Because tunneling and underground construction are among the most hazardous categories of construction work, employers and their contractors are required to comply with California’s Title 8 safety regulations, including those established by Cal/OSHA for underground construction. When safety standards are not followed, and a worker dies as a result, the employer’s liability may extend beyond standard workers’ compensation.
Construction Site Accident Settlement Values in California
Families who lose a loved one in a fatal construction accident may be entitled to pursue compensation beyond workers’ compensation death benefits, particularly when a third party, such as a contractor, equipment manufacturer, or project owner, contributed to the accident.
California wrongful death claims under Code of Civil Procedure Section 377.60 allow surviving family members to seek damages for loss of financial support, loss of companionship and care, funeral and burial expenses, and the deceased’s pre-death pain and suffering through a survival action.
Settlement values in fatal construction accident cases in California vary widely depending on the facts. Attorneys typically use two primary valuation methods. The multiplier method applies a factor of three to five in serious cases, and potentially higher in cases involving gross negligence, to the victim’s annual earnings and benefits. For a worker in their mid-30s with decades of remaining earning potential, this calculation can produce significant figures.
The per diem method assigns a daily dollar value to the victim’s pain, suffering, and loss of enjoyment of life from the date of injury until the time of death. For victims who survived for hours before being recovered, this method captures the conscious suffering endured during that time.
In construction fatality cases involving large public infrastructure projects and well-capitalized contractors, settlements can reach into the millions of dollars. Every case is different, and an experienced California personal injury attorney can assess the specific facts to provide guidance on realistic valuation.
Cal/OSHA Investigation and Employer Accountability
Fatal workplace accidents in California trigger an automatic investigation by the California Division of Occupational Safety and Health (Cal/OSHA). Under Labor Code Section 6302, employers are required to report any work-related death to Cal/OSHA within eight hours of learning of the incident.
Cal/OSHA investigators will examine the tunnel collapse to determine whether applicable safety standards were followed, including those governing underground construction under Title 8, California Code of Regulations, Section 8406 and related provisions. If violations are found, the employer and any responsible contractors may face significant citations and penalties.
Findings from a Cal/OSHA investigation can also be valuable in any civil litigation brought by the victim’s family. Evidence of regulatory violations can help establish negligence and strengthen a wrongful death or survival action claim.
Construction Accident Settlement Calculators
When a family is dealing with the sudden loss of a loved one in a fatal construction accident, understanding the potential value of a legal claim can feel overwhelming. A construction accident settlement calculator is a practical tool designed to help surviving family members and injured workers begin to quantify the financial impact of their loss.
By inputting key details such as the victim’s age, annual income, the nature and severity of the injuries or cause of death, and the degree of fault involved, the calculator applies established legal valuation methods to generate an estimated compensation range. This includes projections based on both the multiplier method, which factors lost earnings and benefits over the victim’s remaining working life, and the per diem method, which assigns a daily monetary value to pain, suffering, and loss of enjoyment of life.
While no online tool can account for every variable in a complex wrongful death or personal injury case, a construction accident settlement calculator gives families a meaningful starting point before their first conversation with an attorney. It transforms abstract legal concepts into concrete numbers, helping families make informed decisions about whether and how to pursue a claim.
GJEL Accident Attorneys provides a construction accident settlement calculator to help those affected by workplace accidents in California take that first step with greater clarity and confidence. Call us now at +1-866-218-3776 to speak with our experts.
Our Commitment: No Fees Unless We Win Your Case
“The loss of life is heartbreaking, and my thoughts are with her family and the coworker who was also injured in this collapse. No family should have to face this kind of tragedy, especially when their loved one simply went to work that day expecting to come home. What happened at the Canyon Tunnel Project raises serious questions about workplace safety and who bears responsibility for these workers being placed in harm’s way. If you lost a family member or were injured in this accident, I want you to know that you have rights, and you do not have to navigate this alone. California law exists to protect workers and their families in exactly these situations, and our team is here to make sure those responsible are held fully accountable. Please reach out to us. The consultation is free, there is no obligation, and you will never pay us a fee unless we win your case.”- Andy Gillin, GJEL Accident Attorneys
GJEL Accident Attorneys has been representing injured workers and families of those killed in workplace accidents throughout California for more than 40 years. We have recovered over $950 million for our clients, and we handle every case on a contingency fee basis, meaning you pay nothing unless we win.
Compassionate GJEL accident attorneys are always available to discuss your case, and you pay nothing unless we secure a favorable outcome. Let our experienced legal team shoulder the legal burden while you focus on what matters most – your family’s healing and recovery. Contact us today at +1-866-218-3776 or visit our Sacramento office for free legal advice.
Local Resources for the Knights Ferry / Calaveras County Area
Calaveras County Sheriff’s Office 891 Mountain Ranch Road, San Andreas, CA 95249 Phone: (209) 754-6500 Website: www.calaveras.ca.gov/sheriff
Stanislaus Consolidated Fire Protection District 3705 Oakdale Road, Modesto, CA 95355 Phone: (209) 552-3600 Website: www.stanfire.org
Modesto Fire Department 1100 I Street, Modesto, CA 95354 Phone: (209) 342-2200 Website: www.modestogov.com/fire
Cal/OSHA District Office (Fresno) 2550 Mariposa Mall, Room 4000, Fresno, CA 93721 Phone: (559) 445-5302 Website: www.dir.ca.gov/dosh
California Department of Industrial Relations (Workers’ Compensation) Phone: 1-800-736-7401 Website: www.dir.ca.gov/dwc
