inorganic is toxic. we don't know from the samples which it was. >> reporter: abc news health and medical editor, dr. richard besser confronted dr. mehmet oz on "good morning america. >> this fear mongering reminds me of yelling fire in a movie theater. i am very annoyed about this. >> i am not fear mongering, we did our home work, spent a lot of time making sure we got our numbers right. >> how can you go on the air and publish arsenic ruts without breaking it down into total, inorganic and organic? >> i disagree, rich, we looked at total arsenic levels. that's what the fda looks at. in addition your assumption that organic arsenic is safe is not true. >> the fda did send a letter to the oz show five days before the program warning them it would be irresponsible to air it. t.j. winick, abc news, new york. >> what is so fascinating the two know each other. they went to medical school together. they are both accomplished doctors.