A minute's silence is to be held for four men - including two from Rotherham - who died when a power station collapsed a year ago today.
Kenneth Cresswell and John Shaw, both from Rotherham, died along with Christopher Huxtable, from Swansea and Michael Collings, from Teesside, when Didcot power station in Oxfordshire collapsed during demolition work.
Mr Cresswell, aged 57, from Clifton and Mr Shaw, 61, from Kimberworth, was trapped under 20,000 tonnes of rubble for a number of months.
Today, officers from Thames Valley Police and the Health and Safety Executive will gather at the site to pay their respects.
Superintendent Rory Freeman said: "Today will, I imagine, be another challenging day for the families who lost their loved ones in this tragic incident.
"My thoughts remain with them and those who suffered injuries, and we continue to support those affected and give them the answers as to why their loved ones lost their lives."
Police said they and the HSE continue to investigate what happened, but it was a 'highly complex investigation' that was progressing 'at pace'.
More than 1,300 statements have been taken and over 2,600 physical and documentary exhibits collected along with 60,000 still images and video.
Detective Chief Inspector Craig Kirby said: "The evidence is being examined by both TVP and HSE, with assistance from forensic archaeologists, metallurgists and structural engineers.
"In the coming months, TVP and HSE will have completed their work at the Didcot site, and the investigation will continue off-site.
"Thames Valley Police and HSE are entirely committed to uncovering why this tragedy happened and will seek justice for those affected, should any wrongdoing be found to have taken place."