Relatives and former workmates of three men who died in a gasworks explosion 45 years ago are being sought to help commemorate the disaster.
The gasworks at Effingham Road, Sheffield exploded in 1973, killing three workers and injuring dozens.
A large underground disused tank in which gas had been stored exploded at the East Midland Gas Board works.
National Grid said it wanted to commemorate Patrick Sleight, Cyril Kennedy and William Donaldson who died.
National Grid are seeking relatives and former workers to commemorate the explosion, which happened on 25 October 1973.
It hopes to create a permanent memorial to those who died or were injured in the blast.
The dead men were part of a group working on the tank that was being prepared to store diesel, according to contemporary reports.
The search comes as the final gasholder in the area is to be dismantled by the company.
Hannah White, from National Grid, said: "It's fitting that as we mark the end of the gasholders in the area that we commemorate the people who lost their lives and who were injured at the gasworks.
"We'd like to hear from relatives or former colleagues of Patrick Sleight, Cyril Kennedy and William Donaldson and anyone else affected by the explosion to explore ways in which we might do that."
To contact the company about the disaster, call free on 0800 8199 071 or email firstname.lastname@example.org .