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The Agency for Toxic Substances and Disease Registry, ATSDR, is an agency of the U.S. Public Health Service. It was established by Congress in 1980 under the Comprehensive Environmental Response, Compensation, and Liability Act, also known as the Superfund law. This law set up a fund to identify and clean up our country's hazardous waste sites. The Environmental Protection Agency, EPA, and the individual states regulate the investigation and clean up of the sites.

Since 1986, ATSDR has been required by law to conduct a public health assessment at each of the sites on the EPA National Priorities List. The aim of these evaluations is to find out if people are being exposed to hazardous substances and, if so, whether that exposure is harmful and should be stopped or reduced. (The legal definition of a health assessment is included on the inside front cover.) If appropriate, ATSDR also conducts public health assessments when petitioned by concerned individuals. Public health assessments are carried out by environmental and health scientists from ATSDR and from the states with which ATSDR has cooperative agreements.

Exposure: As the first step in the evaluation, ATSDR scientists review environmental data to see how much contamination is at a site, where it is, and how people might come into contact with it. Generally, ATSDR does not collect its own environmental sampling data but reviews information provided by the EPA, other government agencies, businesses, and the public. When there is not enough environmental information available, the report will indicate what further sampling data is needed.

Health Effects: If the review of the environmental data shows that people have or could come into contact with hazardous substances, ATSDR scientists then evaluate whether or not there will be any harmful effects from these exposures. The report focuses on public health, or the health impact on the community as a whole, rather than on individual risks. Again, ATSDR generally makes use of existing scientific information, which can include the results of medical, toxicologic and epidemiologic studies and the data collected in disease registries. The science of environmental health is still developing, and sometimes scientific information on the health effects of certain substances is not available. When this is so, the report will suggest what further research studies are needed.

Conclusions: The report presents conclusions about the level of a health threat, if any, posed by a site and recommends ways to stop or reduce exposure in its public health action plan. ATSDR is primarily an advisory agency, so usually these reports identify what actions are appropriate to be undertaken by the EPA, other responsible parties, or the research or education divisions of ATSDR. However, if there is an urgent health threat, ATSDR can issue a public health advisory warning people of the danger. ATSDR can also authorize health education or pilot studies of health effects, full-scale epidemiology studies, disease registries, surveillance studies or research on specific hazardous substances.

Interactive Process: The health assessment is an interactive process. ATSDR solicits and evaluates information from numerous city, state and federal agencies, the companies responsible for cleaning up the site, and the community. It then shares its conclusions with them. Agencies are asked to respond to an early version of the report to make sure that the data they have provided is accurate and current. When informed of ATSDR's conclusions and recommendations, sometimes the agencies will begin to act on them before the final release of the report.

Community: ATSDR also needs to learn what people in the area know about the site and what concerns they may have about its impact on their health. Consequently, throughout the evaluation process, ATSDR actively gathers information and comments from the people who live or work near a site, including residents of the area, civic leaders, health professionals and community groups. To ensure that the report responds to the community's health concerns, an early version is also distributed to the public for their comments. All the comments received from the public are responded to in the final version of the report.

Comments: If, after reading this report, you have questions or comments, we encourage you to send them to us.

Letters should be addressed as follows:

Chief, Program Evaluation,
Records and Information Services Branch,
Agency for Toxic Substances and Disease Registry,
1600 Clifton Road (E-56)
, Atlanta, GA 30333.



From 1947 to 1981, the Stauffer Chemical Company in Tarpon Springs, Florida, made elemental phosphorus from phosphate ore. While the plant was in operation, phosphate slag was transported off-site and used as aggregate in road bedding, road and driveway paving, and in concrete structures. The extent of the distribution could not be determined. Residents in the area expressed concern about possible adverse health effects resulting from exposure to radium and heavy metals leaching from phosphate slag that was used in nearby roads and buildings. Besides radium, other contaminants of concern to residents were arsenic, asbestos, uranium, radon, and ionizing radiation.

There is elevated background radiation from natural radium in phosphate slag and aggregate, but exposures are not expected to result in any adverse health outcomes.

Phosphate slag contains concentrations of metals above background levels. However, based on current epidemiological and medical information the levels are not likely to represent a public health hazard. Combined exposures from roads and driveways are not a health threat. The ATSDR recommends that public health education be provided, to help the public better understand that there is no public health hazard posed by the phosphate slag.



In February 1998, the Agency for Toxic Substances and Disease Registry (ATSDR) received a petition from a Tarpon Springs, Florida, resident. The person requested that the agency investigate health problems that might be associated with exposure to slag materials used in residential areas of Tarpon Springs. Since then, the ATSDR has responded to letters from several other residents. The U.S. Environmental Protection Agency (EPA), Region IV also requested that the ATSDR review the sampling data taken at several vicinity properties near the Stauffer Superfund site in Tarpon Springs. The EPA asked the ATSDR to review chemical and radiological sampling data of residential slag, to evaluate exposure scenarios, to provide radiological dose estimates, and to make recommendations for protection of public health.

Since receiving letters from concerned Tarpon Springs residents, ATSDR staff members have begun investigating residents' health concerns and possible associations between those concerns and exposures to hazardous substances.

A. Site Description and History

From 1947 to 1981, the Stauffer Chemical Company (which operated under different ownership until 1960) made elemental phosphorus from phosphate ore using an arc furnace process. The processed ore was shipped off-site to produce agricultural products, food-grade phosphates, and flame retardants. While the chemical plant operated, waste products (i.e., slag) were disposed of on the plant property, shipped off-site by rail, and given to local residents to be used as fill and aggregate.

The Stauffer plant was added to the EPA Superfund list in 1994 because of pollution on the site. Superfund is a federal program for finding and cleaning up hazardous waste sites in this country. Since 1994, the EPA has been working to clean up the Stauffer site. The EPA is testing and monitoring the soil, water, and air at the site and at vicinity properties to protect nearby residents against health problems that might result from exposure to hazardous waste.

B. Site Visit

In May 1998, ATSDR staff members visited Tarpon Springs to meet with residents and to gather more information. Staff members addressed residents' questions. ATSDR and EPA Region IV personnel visited several vicinity properties in Tarpon Springs and Holiday, Florida. They saw the Stauffer Chemical Superfund site from the site boundary including the Anclote River. During a boat tour on the Anclote River, the ATSDR and the EPA were shown where slag from the site was used to fill in an inlet on site property.

In August 1998, EPA Region IV personnel and staff from EPA's National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama, took samples of building materials and roads and performed radiological surveys of several vicinity properties.

C. Demographics, Land Use and Natural Resources

The City of Tarpon Springs is in Pinellas County, Florida. The community is near the Anclote River, about 1.6 miles east of the Gulf of Mexico. Gulfside Elementary School is directly across the street from the Stauffer site and Tarpon Springs Middle and High Schools are also in close proximity.

According to 1990 census data (1), 9,231 people live within a one-mile radius of the site. About 97% of the population is white and 2.2% are black, with most being middle income level. A hospital, a nursing home, and a children's group home are within one mile of the site. There are about 100 private wells within this same area. The color maps on the following page give a graphical representation of the demographic data (see figure 1).

D. Health Outcome Data

Evaluation of available health outcome data did not find any elevated mortality rates for leukemia, bone cancer, or respiratory diseases. Rates for Pasco and Pinellas Counties were below the state averages for both respiratory disease and childhood leukemia and bone cancers.

Mortality data were analyzed for various respiratory diseases (ICD Codes 460 to 519.9) and for childhood radiogenic cancers (ICD Codes 204 to 204.9) in Florida counties surrounding the Stauffer site. Respiratory diseases were looked at, because of the dusts emitted from Stauffer Chemical when it was operating. The ATSDR used the Wide-ranging ONline Data for Epidemiologic Research (WONDER) system, which is a computer database designed by the Information Resources Management Office, Centers for Disease Control and Prevention (CDC), Public Health Service. The mortality section of the database provided information for comparing the rates of the county with rates for the state and the rest of the country.

Figure 1.
Map of Tarpon Springs, Florida with Demographics and Site:

Figure 1 Thumbnail.

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