January 22, 2020 2:00 P.M.
Convicted: Prestressed Systems Inc. (PSI Inc.), 4955 Walker Road, Windsor, Ontario, a manufacturer of pre-stressed and pre-cast concrete products.
Location of workplace: 5058 Walker Road, Windsor, Ontario.
Description of Offence: One worker was killed and another seriously injured when anchor plates being used in the construction of a bridge girder slid from their supports and failed, striking the workers.
Date of Offence: April 12, 2018.
Date of Conviction: January 20, 2020.
- Following a guilty plea, PSI Inc. was fined $175,000 in provincial offences court in Windsor by Justice of the Peace Susan Hoffman; Crown Counsel Steven Succi.
- The court also imposed a 25-per-cent victim fine surcharge as required by the Provincial Offences Act. The surcharge is credited to a special provincial government fund to assist victims of crime.
- Workers were working on the concrete form for a large pre-stressed bridge girder that PSI had been hired to manufacture for the Nagagami River Bridge project. The process of pre-stressing concrete is a means of increasing the strength of a concrete structure, using tensioned steel cable strands embedded inside the concrete.
- Strands of cable are passed through a concrete form and secured to anchor plates and anchor grips. After the concrete cures around the stressed cables, the exposed ends of the cables are relaxed (de-tensioned) and released (cut).
- To take the tension off the cables, hydraulically powered cylinders are used, and support sleeves are manually removed by workers. During this process, the cable strands act like big elastic bands; when the cable strands are stretched and held, they hold a large amount of stored energy, and proper de-tensioning equipment and procedures are needed to safely remove the tension from the cable strands.
- Four workers were removing the support sleeves from the cylinders when anchor plates – to which the still-stressed cable strands were attached – suddenly failed and struck two of the workers. One of the workers died, another sustained multiple injuries and two others survived without significant physical injury.
- The (then) Ministry of Labour’s investigation determined that one of the key contributing factors to the incident was the company’s failure to use a wire guide on the de-tensioning end of the cable strands as required by the manufacturer of the de-tensioning equipment. Because no wire guide was in place, the anchor plates slid from their supports and catastrophically failed.
- Failure to use the required wire guide constitutes a contravention of section 25(2)(h) of the Occupational Health and Safety Act, which states that “an employer shall take every precaution reasonable in the circumstances for the protection of a worker.”