This collection documents the activities of the Division of Environmental Research (DER) between the years 1952 and 1995. The bulk of the collection consists of raw data collected at various locations for research projects sponsored by private corporations, such as Potomac Electric Power Company and Sun Oil Company. The majority of the remaining portion of the collection consists of the papers of DER Director and Vice President Louis E. Sage. This collection also includes a small body of Dr. Ruth Patrick’s working files from her tenure as Director and Vice President, as well as publications related to environmental research. This collection is divided into five series: "Louis E. Sage papers," "Ruth Patrick papers," "Chemistry data," "Research publications," and "Academy publications." Due to the complex scientific nature of the records, the original order of the collection material has been preserved.

The first series in this collection is the “Louis E. Sage papers,” created by Dr. Sage in his official capacity of Director and Vice President of the DER between the years 1972 and 1995. The series has been divided into four subseries; "Marketing and contracts," "Sponsored projects papers," "Chemistry data," and “Internal procedure papers." The first subseries, “Marketing and contacts,” includes correspondence between Dr. Sage and a variety of his corporate and government contacts. Much of the correspondence mentions DER projects sponsored by the various corporate entities, but does not provide a detailed description of what these projects entailed. This subseries is useful for researching how the DER developed and maintained relationships with the various entities that sponsored DER research projects. This subseries is arranged alphabetically by organization title. The second subseries, “Sponsored projects,” contains correspondence specific to certain projects. These papers provide a general sense of what each project was, but do not provide much information on the findings of these projects. This subseries compliments the “Chemistry data” series, as it demonstrates the administrative interaction of the same projects found in the “Chemistry data” series. The subseries is arranged alphabetically by project name. The project names found in this subseries are the familiar names that Sage used, and are occasionally different from the official project names. The “Internal procedures” subseries contains a collection of blank operational forms used within the DER, such as accident report forms, expense report forms, and professional activity report evaluation forms. These sets of blank forms provide an understanding of the operational procedures that have been followed at DER from the late 1970s to 1995. The subseries is arranged alphabetically by form title. The final portion of the “Louis E. Sage papers” series is the “Personnel files” subseries. This subseries contains a collection of employee evaluations, employee promotion reviews and information on employee salaries. Because of the age and sensitive nature of this material, access to this subseries is restricted until the year 2030.

The second series of this collection is the “Ruth Patrick papers.” This series is very similar to the “Sponsored projects” found in the “Louis E. Sage papers” series. This series contains administrative correspondence dating from between 1956 and 1989 regarding various sponsored projects of the DER. These files were created by Dr. Patrick, and demonstrate the professional relationship she fostered between DER and the DuPont Company and other corporations. The series is arranged alphabetically by project title.

The “Chemistry data” series is the largest portion of the collection, and contains material dating from 1956 to 1985. The series is divided into four subseries: "Working files," "Sponsored projects raw data," "Guadalupe," and "Chalk Point." “Working files” is the first subseries. This subseries contains files on various sponsored projects of the DER. The files include specific information about project development, contract development, project strategies and report composition. These files also include some field notes and raw data within the context of project management and report composition. The original order of this subseries has been maintained. The “Sponsored projects raw data” subseries contains raw data specific to each individual project. The majority of the papers in this subseries are official “Chemical Analysis Data Sheets,” although these files also contain many handwritten field notes as well, demonstrating the activities and findings of the DER project teams between the years 1968 and 1977. The files are arranged alphabetically by project title. The “Guadalupe” and “Chalk Point” subseries both contain information specific to these two projects respectively. These two projects are, therefore, the best documented in the collection. Original order has been maintained for both subseries.

The “Research publications” series contains published material that resulted from the findings of the scientific investigations documented in the sponsored projects files between the years 1948 and 1982. This series also contains Limnology Department Annual Reports and newspaper clippings that chronicle DER activities in various parts of the United States. The material in this series presents the chemistry data contained throughout the collection in a way that is dissociated from the projects. The original order of this series has been preserved.

The “Academy publications” series contains publications from between 1973 and 1993 that describe both the internal and public activities of the Academy of Natural Sciences (ANSP) Limnology Department. These include procedural manuals, project proposals, research reports and the proceedings of various symposiums on environmental studies hosted by the ANSP. The materials in this series demonstrate the public countenance of the DER. The series is arranged by publication date.