predicted that the general population, including susceptible individuals, could experience notable discomfort, irritation, or certain asymptomatic, nonsensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure.

AEGL-2 is the airborne concentration (expressed as ppm or mg/m³) of a substance above which it is predicted that the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape.

AEGL-3 is the airborne concentration (expressed as ppm or mg/m³) of a substance above which it is predicted that the general population, including susceptible individuals, could experience life-threatening health effects or death.

Airborne concentrations below the AEGL-1 represent exposure levels that could produce mild and progressively increasing odor, taste, and sensory irritation, or certain asymptomatic, nonsensory effects. With increasing airborne concentrations above each AEGL, there is a progressive increase in the likelihood of occurrence and the severity of effects described for each corresponding AEGL. Although the AEGL values represent threshold levels for the general public, including sensitive subpopulations, it is recognized that certain individuals, subject to idiosyncratic responses, could experience the effects described at concentrations below the corresponding AEGL.

Phenol is a colorless to pink, hygroscopic solid with a characteristic, sweet, tarlike odor. Pure phenol consists of white-to-clear acicular crystals. In the molten state, it is a clear, colorless liquid with a low viscosity.

Human fatalities by phenol have been reported after ingestion and skin contact. Few studies after inhalation of phenol are available: one occupational study reported slight changes in liver and blood parameters (increased serum transaminase activity, increased hemoglobin concentration, increased numbers of basophils and neutrophils, and lower levels of monocytes) after repeated exposure to a mean time-weighted average concentration of 5.4 ppm (Shamy et al. 1994). Piotrowski (1971) did not report symptoms or complaints in a toxicokinetic study, in which subjects were exposed at 6.5 ppm for 8 h. Likewise, Ogata et al. (191986) in a toxicokinetic field study did not mention any effects on workers exposed to mean workshift concentrations of 4.95 ppm. Among persons exposed to phenol at more than 1 mg/liter (L) of contaminated drinking water for several weeks, gastrointestinal symptoms (diarrhea, nausea, and burning pain and sores in the mouth) and skin rashes occurred (Baker et al. 1978). A geometric mean odor detection threshold of 0.060 ppm (range of all critiqued odor thresholds 0.0045-1 ppm) has been reported (AIHA 1989). Don (1986) reported an odor detection threshold of 0.010 ppm in a CEN (2003) comparable study.