【明報專訊】A SERIOUS INDUSTRIAL ACCIDENT happened a few days ago at an underground site of the MTR Corporation's Elements mall in West Kowloon. Two workers were suspected to have been killed after inhaling biogas. The accident involved working in confined spaces, the definition and requirements of which have been clearly laid down in existing laws — the contractor must ensure that the working environment is safe. It cannot shirk its responsibilities by making the excuse that it "did not know" or "did not think" that the site was a confined space. The truth about why "nobody knew" that the two victims "had not gotten off work" must be fully investigated to demand justice for their families.