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clinmed/2000080009v1 (August 29, 2000)
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Using Land Use History
To Identify Public Health Risks
Dale A. Stirling, Historian
Identifying, characterizing and communicating public health hazards is a challenging task for government agencies and environmental and public health consultants. For instance, the Agency for Toxic Substances & Disease Registry (ATSDR) is required to conduct public health assessments for sites appearing on the U.S. EPA's National Priority List (Superfund). In addition, the ATSDR may also conduct petitioned health assessments. State, regional and county health departments and districts often conduct similar studies as well. In the private sector, consulting risk assessors, environmental health scientists, and toxicologists assess the risk of chemical exposure from a variety of commercial and industrial sources. Unfortunately, these studies fall short in one crucial area--delineating potential threats to human health is rarely based on an understanding of historical uses of a property and its immediately surrounding area. Therefore, federal and local government agencies and consultant studies could benefit by adapting the process and approach taken in conducting real property environmental site investigation site histories.
As provided for in the Comprehensive Environmental Response Compensation & Liability Act of 1980 and the Superfund Reauthorization and Amendments Act of 1986, joint and several liability can be imposed on potentially responsible parties (PRP). This may include absorbing all costs associated with cleaning up contaminated properties. However, PRPs may minimize their liability if they can show by a "preponderance of the evidence" that releases or threatened releases were caused by third parties. In order to qualify for this "third party" defense, the PRP must show at the time they acquired the property that they had no reason to know that a hazardous substance that is the subject of a release or threatened release was disposed on, in, or at the facility. To show this knowledge, PRPs regularly hire environmental consultants to investigate past uses of real property in order to identify the presence of hazardous substances and materials that may impact the environment.
Since the mid-1980s this approach has been successfully used in minimizing liabilities associated with the transfer of commercial and industrial real property. However, the phased site investigation approach has been little used for public health reasons, therefore, a proven site investigation process holds promise as a new approach in delineating public health hazards.
Site History Investigation Process
An important first step is to accurately identify the street address and physical location of the property of interest. This information is readily available from several sources, including city directories (R.L. Polk is the chief publishers of such reference works), real estate atlases, title companies, and county assessor offices. A comprehensive overview of past uses of a property and its improvements will assist in determining the source, extent, and existence of hazardous substances and materials of potential concern in the soil, surface water, groundwater, sediment, and air that may impact public health. A thorough site history accomplishes the following:
The following data sources are useful in characterizing historic and contemporary uses of properties. They are presented in relative order of importance and based on highest return of information versus cost of acquisition.
Compiling a set of photography taken over a period of several decades will evidence land use changes in dramatic fashion. Aerial photography is available from many federal, state, regional, county, and city agencies. The most common sources are the U.S. Agricultural Stabilization & Conservation Service, Geological Survey, and Natural Resource Conservation Service (formerly the Soil Conservation Service); State natural resources and transportation departments; and regional, county, and city planning agencies (the oldest commonly available photography dates to the 1920s). In addition, there are numerous commercial aerial photography studios that have large stocks of historic photography. However, their rates are high compared to government agencies for the reason that much of their stock was purchased from agencies.
Maps represent a treasure trove of land use information. The following types of maps are appropriate to consult when researching land use histories. Topographic maps are useful because they show structures, buildings, utility corridors, and transportation routes. The USGS has published topographic maps of every state and many maps date to the 1880s. These maps are usually available at public and university libraries. In addition, historic topographic maps can be purchased from the USGS on microfiche, microfilm, and CD-ROM. Also, some topographic maps can be viewed on the Internet. Other federal agencies with topographic mapping functions include the Bureau of Land Management, Forest Service, Fish & Wildlife Service, and National Park Service. State, regional, county and even city agencies often produce topographic maps.
Unlike topographic maps, atlases are usually bound maps that feature non-physical related information such as named and numbered streets, lot and plat numbers, and so on. There are a variety of atlases useful for delineating a property's history over time. The most valuable are fire insurance maps that were published by several mapmakers between the 1850s and 1930s. Chief among these is the Sanborn Map Company (currently in business in Pelham, NY). Fire insurance maps were prepared in order to set fire insurance rates, therefore building construction materials were very important, and surveyors for the company would note whether or not a building or structure contained asbestos, thus paying lower rates. But in addition to asbestos, the maps would show in great detail street address, physical layout, and precisely how the building or structure was utilized. The original hand colored maps are in the Library of Congress; however, print outs of these maps can be acquired from several commercial sources. When compiled for a period of years in a specific city, exacting information about a property's land use over time can be delineated.
Other useful atlases include those published for real estate and platting purposes. The best-known real estate atlas makers are the Kroll and Metsker map companies. They published numerous atlases for many major American cities between the turn of the century and the 1960s on an almost yearly basis. Although not as detailed as Sanborn maps, they are useful, especially to identify land uses in years that Sanborn maps were not published.
Building Permits and Plans
Important sources of site history information are the building permits and plans required by most county and city building departments. These records are accurate and time dated. Information may include details about construction materials, subsurface improvements, and installation of objects or sources of environmental contaminants. Reviewing such records for a property over time provides clear detail about land uses.
Land Use and Zoning Records
Documenting land uses and how specific land can be used are the function of county and city land use and zoning departments. These records not only identify property locations, but also included information on allowed uses over time. These departments often have historical records of importance including maps, plats, atlases, aerial photographs, and documentary reports.
Federal, State and Local Environmental & Health Agency Records
Another important source of property use information can be found in the records of environmental and health agencies. These records are created because of regulatory requirements and may include inspection reports, permits, notices of violations, listings of confirmed and suspected contaminated sites, maps, and photographs. In some cases Freedom of Information Requests must be filed to review such records.
Published since the 1880s, these directories exist for most major cities in the U.S. The primary publisher is the R.L. Polk Company and its directories can be found in nearly every public library. When researched over time for a specific address they provide accurate information about who has occupied a property.
Title Searches and Documents
A thorough search for all recorded title instruments for a property for a period of 50-100 years may be useful in identifying past uses. Some title companies provided these as "property title history reports," and included copies of recorded deeds, leases, and easements. Often, these documents will include information about land uses, such as landfilling, underground storage tanks, or chemical stores.
Textual and Archival Records
Written materials are also useful in re-creating land use over time and when supplemented with graphical material provide a comprehensive overview. Textual records of value include books, monographs, dissertations, theses, newspapers, and periodicals related to local history. Non history related textual material that can assist in identifying past property uses include those related to industrial technology, geography, and natural resources. These records are available in many federal, state, local, and university libraries and special collections.
If budgets and scope allow, archival records (including manuscripts) may include land use information. Archival records consist of those records generated by an institutions, agency, or organization and maintained by that entity. Manuscripts consist of business and personal records collected by museums, libraries, archives, and historical societies. For site history purposes, business records will be the most useful because they may contain information about operations and property uses.
All of the site history material previously mentioned is readily available to the land use investigator; however, some consideration should be given to several national companies that specialize in doing such research. There are benefits and disadvantages. In most cases, these companies have purchased regulatory databases from federal, state, and local agencies and can easily provided lists of contaminated sites adjacent to, or even, including the subject site. In addition, the sites of concern are shown on maps. They're easy to read and affordable reports will save time and money. However, some companies also provide site history research services using low paid researchers (often retired title company employees) to sift through historical records. However, this can be accomplished by any one with research experience and there is simply too much liability in relying on someone else to do research of paper based records.
Piecing Together the Puzzle
After the data sources have been gathered and reviewed what is the most useful way to present the information? In written form, the site history report should be a concise narrative of findings supplemented with an outline of the potential hazardous substances and materials of concern found on, in, or adjacent to the property of concern. Alternatively, the information can be presented orally, and supplemented with graphical representations of past uses. Most often, however, the site history will be most useful when information about the potential hazards of substances and materials of concern have been identified in a narrative report.
Information about the hazards associated with exposure to substances and materials of concern can be obtained from a variety of sources. Alternatively, the producer of the report, with appropriate qualifications, can prepare his or her own toxic fact sheets. Preparation of toxic fact sheets will be required when substances or materials of concern are not obtainable from sources of readily available fact sheets. This process requires a great deal of research, primarily of toxicological data, peer reviewed literature, and toxicological profiles. Factual toxicological data or "raw" data as it is referred to at times, is usually obtained from short- or long-term toxicological studies. It consists of basic, non-narrative information about the adverse effects of a chemical or hazardous substance on human health or the environment. There are also a number of sources that provide both factual toxicological data and toxicological literature. These include handbooks, databases, and Material Safety Data Sheets (MSDS). Toxicological literature, which presents the results of raw toxicological data interpretation, is the source of information most often used by toxicologists to obtain information about potential adverse effects of chemicals and hazardous substances. For chemicals not profiled, it is necessary to search the toxicological literature for chemicals and hazardous substances of interest. Such literature consists primarily of peer-reviewed journal articles, but may also include book chapters, monographs, clinical studies, unpublished studies, government agency reports, conference proceedings, and so on. In today’s digital age, access to toxicological literature is readily accomplished in the online environment. Databases that provide abstracts of published toxicological literature include commercial fee-based databases and publicly available databases developed by government agencies, academia, and professional organizations. It is important to note, however, that most online databases only contain literature from the mid 1960s to the present. If information about a chemical is required before that time period, then the indexes or abstracts must be reviewed manually. Toxicological profiles are in-depth reviews of specific chemicals that are based on a thorough review of toxicological literature. Therefore, these are often considered to be the penultimate work determining the adverse effects of a chemical.
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