Final answer:
Phenol, also known as carbolic acid, was once a common disinfectant for surgical wounds but is now considered unsafe for salon use due to its skin irritant properties.
Step-by-step explanation:
A product that was used in the past as a disinfectant but is no longer considered safe for salon use is phenol. Also known as carbolic acid, this chemical was pioneered by the surgeon Joseph Lister for treating surgical wounds in the 1860s. Today, due to its skin irritant properties, phenol is no longer used as a surgical disinfectant.
Other compounds such as triclosan have also been banned due to health concerns. It's noteworthy that halogens like chlorine and iodine continue to be used although strategic measures are required to minimize risks associated with their use.