Re "Injection is just part of fracking" (Letters, Jan. 13): The letter writer is wrong to assert that ammonium perchlorate is a carcinogen.
I refer the reader to the Agency for Toxic Substances and Disease Registry at the Centers for Disease Control, which states that while long term exposure causes thyroid cancer in rats, there is no evidence that perchlorates present a cancer risk to humans.
Because perchlorates are a common chemical in the environment, most people are exposed to low levels of perchlorates with no effect.
Of greater concern to me would be the leakage of the oil-water mixture pumped from the wells. The water is usually highly corrosive and leaks if uncorrected can cause damage to the land and possibly get back in the fresh water table.
-- John Stephens, Fair Oaks