There is no "automatic" right to compensation if you have an accident, whether it be at work or anywhere else; this is the case today just as it was in 1949. It is up to the claimant (the injured person) to bring a claim for negligence against the defendant (the person they blame for causing the accident) and the onus is always on the claimant to prove their claim (save for strict liability claims, which I won't go into here), i.e, demonstrate that the defendant owed them a duty of care, that this duty of care was breached and the accident was a consequence of this breach. Obviously, health and safety law and practices have come a long way since 1949, so, even if the deceased's representatives were able to bring a claim so long after the accident (the limitation period is 3 years from the date of the accident, but there are exceptions) you would need to determine whether the employer was negligent in light of what was known then and what working practices were standard etc.