Unite leaders are writing to the Health and Safety Executive calling for incidents to be investigated properly and lessons implemented across the industry.
The union said it will be pressuring enforcement agencies and employers to step up their efforts to safeguard demolition workers.
Major incidents in 2019 include four deaths at three different sites and the collapse of scaffolding around a derelict shopping centre in Reading.
Unite also highlighted continuing delays into investigations of the tragedies at Didcot, Oxford in 2016 and the 2014 death of man who was crushed after a digger fell through the a concrete slab in Grosvenor Square, London.
Unite national officer for construction Jerry Swain said: “This year has been horrendous for the demolition industry.
“For too long there has been inadequate investigations and responses to accidents and dangerous conditions in the demolition industry and workers continue to pay for that with their lives.
“For instance, why are we are still in a position that closure has not been reached on the four fatalities at Didcot in 2016 or the death at Grosvenor Square in 2014?
“That’s five families still waiting for an outcome, years after the tragedies happened.
“In 2020, Unite demands to know what the industry and enforcement agencies are going to do to address these incidents and ensure next year is a safe year for demolition workers.
“Clients need to take some responsibility for ensuring contractors are employing workers in core activities rather than simply sub-letting everything.
“They could carry out checks on how many workers each contractor covers in the industry’s B&CE Death Benefit Scheme, which provides life insurance.
“That would give them an indication as to how many demolition workers each contractor employs directly. A simple but effective check”