Electric current:

While many deaths due to electric current occur in work environments, many do not. As a fraction of work-related deaths, electrocution is relatively rare (see here(pdf)). Those that are not work related are often due to negligence (e.g. bad electrical wiring) or to recklessness (generally by young men) although both of these issues also contribute to work-related electrocutions. The last of these is easy to deal with the same general rules that prevent one from doing stupid things. The others are a bit harder to deal with. One thing to keep in mind is that electrical problems in houses can lead to threats other than electrocution: many fires are also started by electrical problems.