What electrical hazard, if any, does the starter battery in a vehicle present?

A standard 12-volt vehicle starter battery has very low internal resistance, which allows it to deliver hundreds of amperes in a fraction of a second if the positive and negative terminals are shorted together. This massive short-circuit current can instantly melt tools, cause severe burns, and even lead to a battery explosion or vehicle fire. Because the voltage is only 12 volts, the battery does not present a severe risk of electric shock to the human body under normal conditions, as dry human skin has too much electrical resistance for 12 volts to drive a harmful amount of current. However, the immense short-circuit current makes it highly dangerous if metal tools or jewelry accidentally bridge the terminals.