Why did iron production in India stop?

[Ian]

RhysMichael has touched on an area with which I have some familiarity -- the harmful effects of various metals on people's health -- and correctly reports that various hazardous exposures occur in the mining, refining and working of metals.

These adverse effects have been well understood, if not the exact causes, for at least 400-500 years, and anecdotal accounts of these problems date to Egyptian and Roman times, and possibly earlier.

Galen (c. 150 AD) wrote of the harmful effects of working in sulfur mines. There is a famous treatise by Agricola, De Re Metallica (About Things Metallic), published in 1556 which describes the hazards of mining and metallurgy. Also, an excellent account of metal workers in Bernadino Ramazzini's book, De Morbis Artificum Diatriba (Treatise on the Harmful Effects of Work), published in 1713.

Most heavy metals have considerable toxicity and persist in the body for many years: lead, mercury, cadmium, arsenic, etc.

Iron, itself, is not generally very harmful and is excreted quite readily from the body. Iron is a necessary element for health, being an essential ingredient in hemoglobin where it participates directly in the transport of oxygen in the blood.