Erratum: Halogen radicals contribute to the halogenation and degradation of chemical additives used in hydraulic fracturing (Environmental Science and Technology (2021) 55:3 (1545-15540) DOI: 10.1021/acs.est.0c03685)

The major conclusion that halogen radicals are the key intermediates in the halogenation of chemical additives used in hydraulic fracturing is correct. However, the units of trihalomethane concentrations were inadvertently reported as micromolar ( M) instead of millimolar (mM). We have provided versions of Figure 2 and Table S6 with the correct units. In the caption of Figure 2, we also deleted the redundant references to the presence of 200 mg/L guar and 9.6 mg/L citrate because their concentrations had been specified in the prior sentence. L petroleum distillate, 47.2 mg/L citrus terpenes, 280 mg/L propylene glycol, 400 mg/L borate, and 200 mg/L sodium carbonate. Halide and isopropanol (IPA) concentrations are as indicated. Red, gray, green, and blue asterisk signs (*) represent below the lowest standard concentrations of trichloromethane (8.4 10-5 mM), dichlorobromomethane (6.1 10-5 mM), dibromochloromethane (4.8 10-5 mM), and tribromomethane (4.0 10-5 mM). Error bars represent the range of two replicate experiments.