| John B. King explosion | |
| Date: | June 26, 1930 |
| Time: | 16:30 EST |
| Place: | Brockville, Ontario |
| Cause: | Lightning |
| Casualties1: | 30 |
The John B. King explosion was a Canadian maritime disaster on June 26, 1930, when a drill boat containing dynamite was struck by lightning near Brockville, Ontario. Thirty people were killed.[1]
The scow was off the point of Cockburn Island working on blasting a St Lawrence Seaway channel through Brockville narrows, and had drilled several holes of dynamite. At 4:30 pm, while it was drilling another, a bolt of lightning struck the boat, travelling down the drill, and igniting the dynamite on the river floor.[2]
The explosion was witnessed by United States Coast Guard Cutter 211, which then rescued 12 members of the crew of 42.
A memorial plaque was erected on the north-west corner of Cockburn Island by the Department of Public Works Canada in 1930.
The wreck is now located west of Cockburn Island at a depth of 80 feet.[3] It is a popular dive site, and some divers have lost their lives while diving the wreck.[4]