Cal/OSHA has proposed $212,500 in penalties against the two firms behind the Canyon Tunnel near Knights Ferry, Calif., where an April collapse killed a 35-year-old geologist and seriously hurt a second worker. The bigger share lands on the engineering firm that designed the tunnel, not the contractor that was boring it.
The state’s Division of Occupational Safety and Health announced the citations Oct. 15. Its Mining and Tunneling Unit issued them Sept. 30. Provost & Pritchard Engineering Group of Clovis faces $117,500. Drill Tech Drilling & Shoring of Antioch, the tunneling contractor, faces $95,000. Provost & Pritchard has appealed. The release doesn’t say whether Drill Tech has.
What happened inside the Canyon Tunnel
The ground gave way April 14, about 200 feet in from the portal, and trapped two employees. Twyla Capurro, the geologist, died. Cal/OSHA didn’t name the injured worker, and it didn’t say which firm employed either of them.
The job is a tunnel of more than 12,000 feet for the South San Joaquin Irrigation District, which splits the cost 72/28 with the Oakdale Irrigation District. It bypasses a stretch of the Joint Supply Canal below Goodwin Dam, where an unstable rock slope keeps dropping debris into the channel. SSJID puts the project at $80 million, with completion targeted for 2028.
The tunnel collapse citations, firm by firm
Cal/OSHA’s finding is blunt. Both employers let work go on where dangerous ground had already been identified, without removing it or supporting it, and neither securely supported the section where people were working.
- Drill Tech: one serious accident-related ground control violation and one willful-serious accident-related tunnel support violation, for $95,000.
- Provost & Pritchard: the same two, plus a serious training violation, for $117,500.
“Willful” is the word to watch. It means the agency believes the employer knew about the hazard or the requirement and didn’t act. Each firm drew one.
Why the designer drew the larger tunnel safety penalty
Engineers usually sit outside the citation line on a heavy civil job. Not here. Cal/OSHA treated Provost & Pritchard as an employer with its own exposure underground, and the training citation suggests the agency thinks the firm’s people weren’t prepared to recognize bad ground. California’s tunnel rules require a competent person to inspect ground support at first entry and frequently after. They also require employers to size up each worker’s experience and teach the hazards. A design firm that sends a geologist or inspector to the heading owns those duties for that person.
The fines are small against an $80 million job. They may not be the end of it. Cal/OSHA’s Bureau of Investigations, the unit that reviews cases for possible criminal referral, is running a separate inquiry. Starting Jan. 1, California’s AB 2321 lets prosecutors pursue a willful violation that seriously injures a worker, not only one that kills. It won’t reach back to an April collapse, but it shows which way the state is leaning.
Underground work has been drawing heavier enforcement elsewhere too, like the $648,094 OSHA proposed against six contractors on one New York excavation. For design firms that put field staff past the portal, the practical fix is paperwork plus authority: ground-hazard training on file and a written rule on who can stop the heading. Provost & Pritchard’s appeal now goes to the Occupational Safety and Health Appeals Board, and its outcome will show engineers how far that exposure runs.