Not too long ago I had to help a neighbor jump-start her car. I pulled my car up next to her's and connected the cables to each positive and negative terminal of each battery as I usually do. My neighbor started to panic as she read on the internet that connecting to the negative terminal on a dead battery could cause a spark, which in turn would ignite hydrogen from the dead battery and cause an explosion. I told her I've jumped batteries this way before and nothing bad ever happened, but she wouldn't have it. So I had to search for the metal ground connection in her car's engine (which was put in the most ****ing stupid place by the manufacturers). I eventually found it and got her car started for her. Later on I searched the internet myself and found a lot of material backing what she said about not connecting the cable to the negative terminal of the dead battery. However, whenever I ask people who work in repair shops or people I know that are good with cars, they say there is nothing wrong with connecting the cable to the negative terminal of the dead battery. I'm curious on what other people think. Is it really unsafe to connect the jumper cable to the negative terminal of the dead battery? Or is that basically an old wives tale?