www.liverpoolecho.co.uk/news/liverpool-news/17-deaths-250-tonnes-explosive-13696923
The Liverpool Echo has the story on its web site – see link above

These are the tickets my family were given when we walked through the new (2nd) Tunnel in 1971, the day before it opened to vehicles.
I have always been fascinated by the Mersey Tunnels, their history and how they were constructed. This Liverpool Echo article gives an interesting insight into both of them.