As has been custom for the past 30 years, Canada marks a National Day of Mourning on April 28 to commemorate those who have died or been injured in workplace accidents or are suffering  due to occupational disease.It would be wise for Canadians to take some time on this year's Day of Mourning to think about prevention.According to the latest available statistics, 1,081 workers were killed in workplace accidents in 2021. This represents a 16-per-cent increase from the 2020 total of 924 deaths. It was also well over the yearly average of 945 since 2009 and represents almost five workplace deaths every working day.Let me repeat, in Canada on average, we experience five workplace deaths every day. By any measure this is far, far too many.Also up were workplace injuries at 277,225 in 2021 from 253,397 the previous year, representing a nine per cent increase.The situation gets more disturbing when one considers that these numbers are probably understated.This is because the official numbers only represent approved compensation claims. Left out are injuries that go unreported or claims that are denied, or workers not covered by compensation systems at all.As far as safety on construction sites go, a 2021 study by the Institute for Work and Health found that lost-time injury claims to the Workplace Safety and Insurance Board (WSIB) are 31 per cent lower on unionized building trade construction jobs than they are in a non-union environment.However, not all construction workers are unionized and although the unionized industry has a superior safety record, we still have a long way to go. Unfortunately, the entire industry despite our advances and utilization of best practices, when taken as a whole, union and non-union construction is the fourth highest occupation group for workplace fatalities at 20.2 deaths per 100,000 workers. Falls are the common cause of death. Other risks include falling objects, electrocution and spills.If history has taught us anything, it's that more needs to done to protect workers.In 1952, a support collapsed on the Second Narrows Bridge - a highway bridge being constructed between Vancouver and North Vancouver. Seventy-nine 79 workers fell, 23 were killed - mostly iron workers, along with two engineers and a crane operator. This remains one of British Columbia's worst construction accidents.And, it's been just over a decade since a Christmas Eve construction accident killed four migrant workers in Toronto when the swing-stage they were working on collapsed.Human nature being what it is, we too often have to wait until disaster strikes before we start thinking in earnest about prevention. A case in point is the May 1992 Westray Mine disaster in Nova Scotia in which 26 miners needlessly died.Since the mine opened the previous year, it had been plagued by safety complaints and warnings by the miners of danger. A commission of inquiry subsequently found the mine's owners were negligent about the safety of employees.In addition, the federal labour code was amended to give employees the right for the first time to refuse work they consider dangerous.And in 2004, the so-called Westray law was enacted to amend the Criminal Code to establish criminal liability of corporations for workplace deaths and injuries.Unfortunately, the Harper government in 2014 weakened the definition of danger to make refusal of work more difficult. And the Westray law is rarely enforced.We need to recapture the Westray legacy and protect workers on job sites in the future. Clearly workplace fatalities would decrease if it was made easier for workers to refuse to work due to safety concerns.Let's reflect upon our collective purpose, let's remember, acknowledge and offer our deepest gratitude to those who have been injured, fallen ill or lost their life while at work.Their suffering and loss have led to much needed reforms that serve to prevent injuries, illnesses and deaths.But we also owe it to them and others in the future to commit to doing all that we can to make sure every worker goes home safe. Prevention -  including creating an environment where workers can refuse unsafe work - is part of the solution.Sean Strickland is the Executive Director of Canada's Building Trades Unions, representing 600,000 skilled trades workers.