Robert Bunsen is most famous for inventing the Bunsen burner, which he technically did not invent. What he's not famous for is much more interesting. His most altruistic research, which has saved many lives, very nearly killed him, and led to to the research that gave us the burner.
Chemists in the 19th century were a varied lot, but they could be characterized by one common trait: a spectacular lack of concern for their own safety. If anything stunk, boiled, burned, exploded, or emitted poisonous fumes, there was a chemist standing right beside it. So it's fitting that Robert Bunsen, a budding scientist with an interest in chemistry, spent his free time gamboling up to the edges of volcanoes to collect the fumes and rigging pressure-driven geysers in his office. It's also fitting that his favorite area of study (in chemistry at least) was arsenic.
Everyone knew that arsenic was poisonous; it had been used to dispatch people since Roman times. Bunsen turned his sights on cacodyls, which are made up of a number of different chemicals, all of which seemed to be poisonous, but none of which, besides arsenic, anyone had really figured out yet. Bunsen's reports on the subject include cheerful lines like "the smell of this body produces instantaneous tingling of the hands and feet, and even giddiness and insensibility" and "it is remarkable that when one is exposed to the smell of these compounds the tongue becomes covered with a black coating."
His tongue was not blackened in vain. Bunsen discovered a treatment for arsenic poisoning that is still used today. Iron oxide hydrate, or ferric hydrate, is only useful on arsenic that's still in the stomach, but it's a lot better than last rites. The compound basically grabs hold of dissolved arsenic in a solution, and makes it into indissoluble and indigestible arsenate of iron. Basically, the iron forms rust with the arsenic, and the body doesn't digest the poison.
Sadly, this is not the only danger of cacodyls. Among their many other objectionable traits is a tendency to spontaneously combust when exposed to air. Bunsen accidentally exposed his materials to air and set off an explosion that cost him an eye. After his brush with death and blindness he moved on to spectroscopy, the science of using the light a burning substance emits to analyze what atoms the substance contains. In order to get a good flame, he modified an existing burner, and his modifications came to be known as the Bunsen burner. And that's how one explosion in a lab altered the course of scientific history.