40 CFR § 125.121 - Definitions.
(a) Irreparable harm means significant undesirable effects occurring after the date of permit issuance which will not be reversed after cessation or modification of the discharge.
(b) Marine environment means that territorial seas, the contiguous zone and the oceans.
(c) Mixing zone means the zone extending from the sea's surface to seabed and extending laterally to a distance of 100 meters in all directions from the discharge point(s) or to the boundary of the zone of initial dilution as calculated by a plume model approved by the director, whichever is greater, unless the director determines that the more restrictive mixing zone or another definition of the mixing zone is more appropriate for a specific discharge.
(d) No reasonable alternatives means:
(1) No land-based disposal sites, discharge point(s) within internal waters, or approved ocean dumping sites within a reasonable distance of the site of the proposed discharge the use of which would not cause unwarranted economic impacts on the discharger, or, notwithstanding the availability of such sites,
(2) On-site disposal is environmentally preferable to other alternative means of disposal after consideration of:
(i) The relative environmental harm of disposal on-site, in disposal sites located on land, from discharge point(s) within internal waters, or in approved ocean dumping sites, and
(ii) The risk to the environment and human safety posed by the transportation of the pollutants.
(e) Unreasonable degradation of the marine environment means: (1) Significant adverse changes in ecosystem diversity, productivity and stability of the biological community within the area of discharge and surrounding biological communities,
(2) Threat to human health through direct exposure to pollutants or through consumption of exposed aquatic organisms, or
(3) Loss of esthetic, recreational, scientific or economic values which is unreasonable in relation to the benefit derived from the discharge.