Always wear safety glasses when charging, disconnecting, jump starting, etc. car batteries (lead acid). The small amount of hydrogen generated can ignite from a

Always wear safety glasses when charging, disconnecting, jump starting, etc. car batteries (lead acid). The small amount of hydrogen generated can ignite from a spark, and it's enough to explode the top and shoot plastic scrapnel everywhere. It won't seriously injure your meatier bits, but it's more than sufficient to take out an eye.