A process covered under 40 CFR Part 68 is eligible for Program 1 requirements if it meets all of the criteria listed in 40 CFR §68.10(b). One of those criteria is that the distance to a toxic or flammable endpoint for a worst-case release assessment is less than the distance to any public receptor. Are rivers that are used for recreation covered as "public receptors"?
The final rule defines public receptors to mean "offsite residences, institutions (e.g., schools, hospitals), industrial, commercial, and office buildings, parks, or recreational areas inhabited or occupied by the public at any time without restriction by the stationary source where members of the public could be exposed to toxic concentrations, radiant heat, or overpressure, as a result of an accidental release" (40 CFR §68.3). A river would be included in this definition if it is likely to be used for recreational purposes where members of the public may be present.