The primary chemical precursor to TCA is TCP (2,4,6-trichlorophenol), an anti-microbial agent used in processing wood. Molds (and some suspect bacteria such as Streptomyces) are able to de-toxify TCP by methylating the -OH to -OCH3, which is not toxic. Chlorinated phenols can form chemically when hypochlorous acid (HOCl, one of the active forms of chlorine) or chlorine radicals come in contact with wood (untreated, such as barrels or pallets.) The use of chlorine or other halogen-based sanitizing agents is being phased out of the wine industry in favor of peroxide or peracetic acid preparations. Chlorine dioxide has not been shown to produce these spontaneous chlorophenols. Chlorine dioxide is a relatively new agent being used in the wine industry due to its obvious advantages, having shown no evidence of the possibility of TCA formation. "Wine Spectator" has reported that such California wineries as Pillar Rock Vineyard, Beaulieu Vineyard, and E & J Gallo Winery have had trouble with systemic TCA.