Digging Deep, Staying Safe: Excavation Awareness

Under provincial OHS regulations across Canada - including Alberta OHS Code Part 32, Ontario O. Reg. 213/91 Part III, and BC OHS Regulation Part 20 - no worker may enter a trench deeper than 1.2 metres (4 feet) unless a protective system is in place. The only exception is an excavation cut entirely into solid, unfractured rock confirmed by a competent person. Three protective systems qualify: sloping (cutting trench walls back at a safe angle), shoring (bracing the walls with hydraulic or timber supports), or a trench box (a prefabricated shield placed inside the trench). There are no exceptions for short-duration tasks - soil does not care how long you plan to be inside.

Canadian OHS regulations - including Canada Occupational Health and Safety Regulations Part III, Alberta OHS Code Section 454, and BC OHS Regulation Section 20.80 - require every excavation site to have a designated competent person who is qualified through knowledge, training, and experience, familiar with the applicable regulations, and capable of identifying actual and potential hazards. This role carries legal accountability: the competent person must inspect the trench before each shift, classify soil type, select the appropriate protective system, and stop work immediately if conditions become unsafe. The designation must go to someone genuinely qualified - not simply whoever is available on site.

Do not enter the collapsed trench - secondary collapses are extremely common and will likely happen within seconds, turning a rescuer into a second victim. The correct steps are: call 911 immediately (trench rescue requires specialized equipment and trained personnel), secure the perimeter to prevent others from approaching, and shut down all nearby equipment to reduce vibration and soil movement. Emergency preparedness requirements for excavation sites are outlined under Canada Labour Code Part II, Alberta OHS Code Part 7, and BC OHS Regulation Part 3. According to documented Canadian trench rescue cases, would-be rescuers who entered collapsed trenches without specialized equipment became additional victims in the majority of cases.

Yes - locating underground utilities through your provincial 'Call Before You Dig' service before breaking ground is a legal requirement under provincial OHS regulations, not a recommendation. Failure to call is consistently identified as a leading cause of serious and fatal incidents on Canadian worksites. Each province operates its own locate service: Ontario One Call (ontario1call.com), Alberta One Call (albertaonecall.com), and BC One Call (bconecall.com) are among them. After calling, you must wait for the confirmation ticket and physical markings on the ground - never assume utility maps are current or complete, as buried lines shift, get rerouted, and are sometimes mapped incorrectly.

A competent person must classify soil before protective systems are selected, using visual and manual tests required under provincial regulations such as Alberta OHS Code Section 461 and BC OHS Regulation Section 20.82. The most dangerous classification, Type C, includes granular materials like gravel and sand and any soil with active water seepage - it requires the most conservative protective measures. Any previously disturbed soil (such as backfill from a prior excavation) is also weaker than undisturbed ground, even if it looks solid. Critically, conditions can change overnight: a single rainstorm or freeze-thaw cycle can shift soil from a stable classification to Type C, so the competent person must re-inspect the trench after any significant weather event before work resumes.