experience notable discomfort, irritation, or certain asymptomatic, non-sensory 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 but transient and nondisabling odor, taste, and sensory irritation, or certain asymptomatic, non-sensory 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 susceptible subpopulations, such as infants, children, the elderly, persons with asthma, and those with other illnesses, it is recognized that individuals, subject to idiosyncratic responses, could experience the effects described at concentrations below the corresponding AEGL.
Ethylenimine is a volatile, clear, colorless, flammable explosive liquid that has an odor similar to that of ammonia and an odor threshold reported as 2 ppm in air; however an odor detection (OD50) was reported as 0.698. It is a very reactive direct-acting alkylating agent, the activity of which is similar to that of nitrogen and sulfur mustards. It is also very caustic, attacking numerous substances including plastics, metals, and glass that does not contain carbonate or borax. Estimates of annual U.S. production of ethylenimine range between 1.65 and 4.85 million pounds prior to 1994. Ethylenimine is used in the manufacture of products such as triethylenemelamine, paper, textile chemicals, adhesive binders, and petroleum refining chemicals. Ethylenimine is stored in 320-pound cylinders, but shipping quantities are unknown.
Relevant data on ethylenimine consisted of only a few case reports in humans and acute inhalation lethality studies in laboratory animals. Toxicity due to exposure to ethylenimine is generally delayed and includes irritation to contact organs (skin, eyes, oral cavity, and upper and lower respiratory tract), systemic toxicity, and death depending upon the concentration. At extremely high concentrations, however, irritation to contact organs may occur during or soon after exposure. The time course of irritation caused by ethylenimine is different from that caused by primary irritants such as ammonia, which causes an immediate response upon exposure regardless of concentration.