If it's safe to ship tons of LNG on big ships there's almost certainly a way to ship batteries safely. It might take a few 'incidents' though before best practise becomes clear.
In a similar direction, I was thinking of the zillions of gallons of petroleum products that have accidentally ended up in ecosystems during transport.
[1]: https://gcaptain.com/a-short-list-of-major-oil-spills-from-s...