Question: When did health care workers first use chlorine solution to decontaminate hands?
Disambiguated questions and answers: question: When did health care workers first use chlorinated lime to decontaminate hands?
When did health care workers first use chlorine-water to decontaminate hands?
answer: 1828
1847
Natural Questions answer: 1847 (from the Wikipedia article "Ignaz Semmelweis")