In late 1991, the Florida Keys National Marine Sanctuary (FKNMS) was formed to develop policies in regard to the protection of the reef. The Water Quality Steering Committee and the Technical Advisory Committee of the FKNMS were formed to evaluate data concerning degradation of water quality and to make recommendations based on this data to the FKNMS. The Key West outfall had been a major target of local groups in their efforts to improve water quality.

               The US EPA studies spanned a period of over a year and incorporated NOAA tidal current velocity data with water quality sampling, fluorescent tracer dye studies, nitrogen and carbon isotope enrichment studies and chemical and biological benthic evaluations. In the report summarizing the data collected, Dr. Roland Ferry of the US EPA reached the conclusion that there was no measurable impact on the environment from the discharge at the ocean outfall. The report indicated that nitrogen and phosphorus in Key West and Garrison Bights were five times higher than the level at the outfall and levels north of the outfall were also above the level in the vicinity of the outfall. The conclusion to be drawn from this information is that the discharge at the outfall was a negligible contributor to the decline of water quality and the reef in the Key West area. 

               The data and conclusions in the EPA reports were supported by the FDEP report on sampling performed by their staff at the outfall. The water column and benthic analyses again showed no significant difference in the health of the environment in this area when compared to a remote location with similar and bottom structure. The data were also consistent with the water quality data collected by OMI for the City of Key West over the previous seven years. Both the FDEP and the NPDES operating permits required the Outfall Monitoring Program.  It consisted of quarterly testing of the whole effluent for all Florida Class III Marine Waters criteria and quarterly testing of samples sites at the outfall during both flood and ebb tide phases as well as testing of an unaffected background station. The surface water sites were sampled at three depths at each site and tested for a variety of water quality indicators, including chlorophyll A, nitrogen, and phosphorus and dissolved oxygen. These parameters are typical indicators of water quality, and in every instance, there was no measurable difference between the sites at the outfall and the background site.