Metol (or Elon, in Eastman Kodak parlance) is a developing agent used in photographic developers.

Because it has been in use for this purpose for over 100 years and often by amateur photographers , there is a wide body of evidence about the health problems that contact with Metol can cause. These are principally local dermatitis of the hands and fore-arms as well as some evidence of sensitization dermatitis in which subsequent exposure triggers of a chronic condition that is resistant to medication. The use of Metol in highly caustic solutions and the presence of other materials in dark-rooms that have been implicated in dermatitis such as Cr(VI) salts, may exacerbate some health impacts.