EnvironmentalStats for S Plus : User’s Manual for Windows and UNIX ENVIRONMENTALSTATS for S PLUS a new add on module to S PLUS is the first comprehensive software package for environmental scientists engineers and regulators. ENVIRONMENTALSTATS for S PLUS provides a set of powerful yet simple to use functions for performing graphical and statistical analyses of environmental data including parameter and quantile estimation methods for dealing with non detects power and sample size calculations prediction and tolerance intervals and probabilistic risk assessment. ENVIRONMENTALSTATS for S PLUS includes an extensive hyptertext help system that explains methods from the environmental literature and regulatory guidance documents along with a glossary of commonly used statistical and environmental terms. This users manual provides the documentation for Versions 1.0 and 1.1 of the ENVIRONMENTALSTATS for S PLUS module. Version 1.0 works under S PLUS 3.3 3.4 and Version 1.1 works under S PLUS 4.0