We have studied the effect of two detoxifying factors on aqueous solutions of phenol: UV radiation from different sources, and humic substances. The phenol photoconversion processes were monitored by the fluorescent method; the toxicity of the phenol solutions was monitored using a bioluminescence test. It was shown that effective detoxification of an aqueous phenol solution occurs as a result of addition of humic substances; the most effective photoinduced detoxification was detected when using UV radiation from an exciplex lamp (λrad = 308 nm). Other UV irradiation sources and the combined action of UV irradiation and humic substances are characterized by a smaller detoxifying effect. In this case, irradiation using an exciplex lamp (λrad = 222 nm) increases the toxicity of the phenol solution both in the presence and in the absence of humic substances.