National Toxicology Program

European Producers:

• Dow Chemical (Nederland) BV Temeuzen, (Zeeland) Netherlands [SRI, 1989]
  

• Rutgerswerke AG Duisburg, Germany [SRI, 1989]
  

• Shell Nederland Chemie BV Moerdijk, (Noord Brabant) Nederland/Rotterdam-Pernis, (Zuid Holland) Netherlands [SRI, 1989]
  

Importers:

• Dow Chemical Company Midland, Michigan [USEPA, l990c]
  

• Mitsubishi New York, New York [USEPA, l990c; USEPA, 1987]
  

• Neville Chemicals Santa Fe Springs, California [USEPA, l990c; USEPA, 1987]
  

• Ashland Chemical Dublin, Ohio [USEPA, l990c; USEPA, 1987]
  

3. Volume

The United States International Trade Commission (USITC) reports the following production data for dicyclopentadiene (including cyclopentadiene):

The production volume of dicyclopentadiene is reported in the public file of the EPA Toxic Substances Control Act (TSCA) inventory. In 1977, 11 manufacturers listed as producers of dicyclopentadiene reported a total production volume ranging from 53,200,000-282,000,000 pounds [USEPA, l990c].

The following maximum production levels of dicyclopentadiene in 1980 at the following plants have been reported:

At the time these data were published, it was predicted that Exxon's capacity would rise to 50 million pounds per year in mid 1981 and to 80,000,000 pounds by 1982. Carbide and Exxon were the only producers of high purity dicyclopentadiene in 1980.

The demand for dicyclopentadiene in 1979 was 90 million pounds. In 1980, the demand for this compound had remained unchanged, and in 1984 the demand had risen to 115 million pounds. The historical growth for dicyclopentadiene (1969 - 1979) was 4.8% per year. In 1980, growth was predicted to be 4.9% through 1984. In 1980, it was reported that the markets for ethylene propylene diene monomer elastomers had remained among the strongest of the available rubber products, and that dicyclopentadiene's use as an intermediate in the production of unsaturated polyester resins was expected to grow. At the same time, this compound's use in pesticides was declining and several competing dienes which can be used in the vulcanization of ethylene propylene diene monomer elastomers were on the market [Kavaler, 1980].

The United States Department of Commerce reported that the total volume of dicyclopentadiene imported between 1985 and 1988 increased by 30%. The major exporters of dicyclopentadiene to the United States during this period included the Netherlands, Japan, and Belgium [U.S. Department of Commerce, 1986-1989]. A breakdown of the net quantity of dicyclopentadiene exported to the United States by country for the years 1985 through 1988 is presented in Table 1.

* Imports for consumption is a measure of the total of merchandise that has cleared through Customs, whether such merchandise enters consumption channels immediately, or is withdrawn for consumption from warehouses under Customs custody, or is entered into U.S. Customs territory from Foreign Trade Zones.

4. Technical Product Composition

Dicyclopentadiene exists in two stereoisomeric forms, the endo- and the exo-isomers. The commercial product is primarily the endo-isomer [Kirk-Othmer, 1979].

Dicyclopentadiene is available from Aldrich Chemical company at 95% purity [Aldrich, 1988]. Dicyclopentadiene is also available at 97% purity [U.S. Coast Guard, 1985]. Dicyclopentadiene is available in a crude form at ³ 50 wt%. A high purity form is available in the United States and Europe between 70 to 95 wt%. Depending on the distillation process, impurities may include light Cs-hydrocarbon fractions [Kirk-Othmer, 1979]. Industrial grade dicyclopentadiene consists of approximately 95% endo-dicyclopentadiene. The other constituents are predominantly the exo-isomer, methyldicyclopentadienes and tricyclopentadiene [Van Breemen, et al., 1987].

B. Use

• Production of hydrocarbon resins that result in the end-use manufacture of adhesives, rubber tackification, surface coatings, and resin replacements [Kirk-Othmer, 1979].
  

• A precursor in the production of elastomers [Kirk-Othmer, 1979], polymers, and perfumes [Van Breemen, et al., 1987].
  

• An intermediate in the production of chlorinated derivatives for the production of pesticides [Sax and Lewis, 1987]; however, this use is limited to termite control substances [Kirk-Othmer, 1979].
  

• Stabilizer for organophosphorus insecticides [USEPA, 1987].
  

• An intermediate used in flame and fire retardant chemicals [Kirk-Othmer, 1979; Sax and Lewis, 1987].
  

• Jet fuel component [Kirk-Othmer, 1979].
  

• The following pattern of use was reported in 1980 [USEPA, 1987]:
  • Ethylene-propylene diene monomer elastomers: 40%

  • Hydrocarbon resin systems: 30%

  • Unsaturated polyester resins: 10%

  • Miscellaneous (e.g., flame retardants, pesticides and agricultural chemicals, fuel and lube additives, adhesives): 20%.
    

B. Occupational Exposure

Wildlife officers monitoring a basin contaminated with dicyclopentadiene were reportedly exposed to this compound [NIOSH, 1981]. In addition, laboratory research personnel were accidentally exposed to dicyclopentadiene while performing toxicity testing [Kinkead, et al., 1971]. The concentrations of dicyclopentadiene to which the wildlife officers and researchers were exposed were not reported.

Data from the National Occupational Exposure Survey (NOES) conducted by NIOSH between 1981 and 1983 indicate that 1,122 workers, including 85 female employees, were potentially exposed to dicyclopentadiene in the workplace [NIOSH, 1990].

C. Environmental Exposure

The presence of dicyclopentadiene in the environment is caused by the land disposal of pesticide wastes [Spanggord, et al., 1979]. Dicyclopentadiene has been detected in drinking water, ground water, soil, and in waste water effluents near user facilities in certain locations in the United States [NIOSH, 1981; Spanggord, et al., 1979]. Dicyclopentadiene is a contaminant of certain ground water supplies in Colorado, as a result on the disposal of pesticide wastes in unlined ponds, and from deep-well injection at the Rocky Mountain Arsenal. Although the disposal of such wastes had ended by 1966, dicyclopentadiene residues in sub- to low-ppm ranges are still detectable in some well water supplies [Ivie and Oehler, 1980].

Because many derivatives of dicyclopentadiene have been detected in ground water extracts from the Rocky Mountain Arsenal, it is evident that extensive transformation of this compound can occur in the environment. In one study of this area, eight derivatives of dicyclopentadiene were detected by gas chromatography-mass spectrometry (GC/MS) in direct methylene chloride extracts of ground water. Five derivatives were observed in methylene chloride extracted charcoal, which had been used to filter ground water in a water treatment system at the Rocky Mountain Arsenal. Three derivatives were found in both extracts. The majority of the derivatives found were oxygenated, with the addition of one, two, or three oxygen atoms, and in other cases with the loss or addition of two hydrogen atoms. Incorporation of sulfur or one carbon and two hydrogen atoms had also occurred. The authors stated that spontaneous oxidation of dicyclopentadiene by atmospheric oxygen might occur, but that bacterial metabolism is probably responsible for the derivatives observed [Van Breemen, 1987].

A study on the environmental fate of dicyclopentadiene has been conducted by the Department of the Army. From the results of this study, it was concluded that the photolysis of dicyclopentadiene occurs in the presence of natural water sensitizers. This indirect photolysis occurs slowly, with a half-life of approximately 76 days. In addition, biotransformation occurs very slowly in water and soil. Biodegradation in both soil and water appears to slow with decreasing temperature, and only very small amounts of biodegradation have been found to occur at 10^oC [Spanggord, 1979]. It is estimated that the biodegradation half-life ranges from 4 to 7 years in soil and from 1 to 2 years in water at 25^oC. The estimated volatilization half- life for dicyclopentadiene is 5 years and therefore, volatilization is considered to be a primary fate of this compound [Spanggord, 1979].

In 1977, The U.S. Army Medical Bioengineering Research and Development Laboratory recommended temporary guidelines for dicyclopentadiene in the accessible environment. The following guidelines were based on the results of mammalian toxicity tests:

Food	1.3 ppm
Drinking water	1.3 ppm
Water: for recreation 1	3.0 ppm
Water: to protect aquatic life	0.5 ppm
Water: for irrigation	20.0 ppm

[Burrows, 1977]

The OSHA permissible exposure limit (PEL) is 5 ppm (30 mg/m³) averaged over an eight-hour work shift. A short-term exposure limit (STEL) has not been determined [OSHA, 1989].

The Food and Drug Administration (FDA) has approved the use of dicyclopentadiene in adhesives, rubber articles intended for repeated use, and in polymers for inclusion in food packaging [Office of the Federal Register, 1990]

E. Exposure Recommendations

The ACGIH-recommended threshold limit value-time weighted average (TLV-TWA) is 5 ppm (27 mg/m³) [ACGIH, 1989].

There is no NIOSH-recommended exposure limit (REL) for dicyclopentadiene.