I ordered new Yusasa YN16 off ebay and it turned up today and was dumped on the door mat by courier in spring sunshine, after float charger boiled 4yr old battery on 916. Got home and started to unpack it from shrink wrapped box with battery shrink wrapped inside. As I gently run stanley blade a long edge of battery could not help but notice it was a bit swollen in center of battery.... As I peeled shrink wrap away there was a puff of vapour as battery bung shot out and I bore brunt in left ear/nostril/eye. Luckily eye and plughole ok, but left nostril feels like it's had a heavy weekend on marching powder.... Be safe out there folks!
Pleased you are OK. I recently purchased 4 lead acid leisure batteries and was really impressed with how the sending company had packaged them. Each was in an individual cardboard box with a warning sticker to open in the outdoors. Inside the cardboard box each battery was cocooned in inflated protective packaging on all sides. Each battery was then enclosed in a vacuum seal bag. It took ages to get the batteries out, but having read your account I can see that the company I bought from (it was an eBay purchase) took safety seriously.