Ms. Courtney R. Johnson
IRIS Submission Desk
National Center for Environmental Assessment
U. S. Environmental Protection Agency
Washington, D. C. 20460

Re: Comments on the Integrated Risk Information System (IRIS); Announcement of the 2000 Program; Request for Information

Dear Ms. Johnson

I. INTRODUCTION AND SUMMARY

The Color and Additive Compounders Division (CACD) of The Society of the Plastics Industry, Inc. (SPI) would like to offer the following comments to the Integrated Risk Information System (IRIS) in response to the announcement of the IRIS 2000 Program request for scientific information on health effects that may result from chronic exposure to chemical substances. The members of the CACD (and many non-member companies within the plastic industry) formulate color concentrates for plastics, compound plastic products, or otherwise use plastics that contain substances listed in the IRIS 2000 Program. CACD feels that in addition to the members of the plastics industry, the consumer will also be directly or indirectly affected by the decisions of the IRIS 2000 Program.

The CACD membership supports the purpose of the IRIS Program and believes it is important that the IRIS Program continue to perform periodic reviews of chemical substances to determine their potential impact to human health. We also believe the IRIS Program should identify all substances that pose a significant risk to human health and the environment. However, we also feel that during its evaluation of the available scientific study data, members of the IRIS Program should consider the often significantly different risk potential posed by individual chemical substances or compounds within a general chemical category or group. The IRIS evaluation should also consider cases where the subject chemical substance is compounded into a medium, such as plastic resin, that permanently binds the substance in a form that reduces or eliminates its health risk potential. Finally, the IRIS evaluation should also consider the health history of general industry personnel who handle these materials on a routine basis or the consumer using final products that may contain the subject substance.

II. Risk Potential Differences Within a Chemical Category

The IRIS Program should consider the differences in risk potential posed by individual chemical substances within a chemical category; for example: cadmium compounds. The cadmium compound used as pigments to formulate color concentrates within the plastics processing industry, calcined cadmium-zinc-sulfide (cadmium sulfide) and cadmium-sulfo-selenide (cadmium selenide), are extremely insoluble forms of cadmium. These cadmium compounds have an LD50 greater than 5000 mg/kg in rats. When compared to a more soluble form of cadmium, such as cadmium oxide with an LD50 of 72 mg/kg in rats (Fielder & Dale 1983, cited in Krajnc et al. 1987), it becomes obvious that there may be a significant difference in the health risk potential between individual compounds within a chemical category.

A study of monkeys exposed to cadmium sulfide dust aerosols found that cadmium did not accumulate in the kidneys as was noted for more soluble forms of cadmium compounds (Oberdorster & Cox 1989, cited in IARC 1993). Another study reported that the low levels of cadmium found in Winstar rats after exposure to cadmium sulfide dust was later cleared from the lungs and excreted in feces (Klimisch 1993, cited in ECB 1996).

The EPA external draft Toxicological Review of Cadmium and Compounds, dated March 4, 1999, reported "Typical environmental contributions (i.e., not near smelting operations) to the dietary intake of cadmium are considered negligible." (see pg. 9, Section 3.5.3). Relative to studies and data presented on oral administration of cadmium, the document further stated "These data are not compelling or rigorous enough to raise a carcinogenic concern by the oral route for cadmium." Cadmium and compounds exist in a variety of forms, from free soluble salts to nearly insoluble complexes like cadmium pigments. The explicit recognition that differences in health risk potential exist between different forms of compounds will ensure the IRIS Program evaluation review process is scientifically fair and accurate.

III. IRIS Listing and Potential Impact to the Plastics Processing Industry

Significant data has been presented over the years, indicating the manufacture, processing and handling of cadmium pigments has not presented a health risk to industry employees or consumers. When encapsulated in a synthetic polymer, the likelihood of exposure to cadmium is even further reduced or eliminated. However, adverse publicity that has resulted when various regulatory agencies have made announcements about general health and environment impacts that grouped all cadmium compounds into one category has resulted in a very significant market loss for plastic products containing insoluble cadmium compounds. These products not only pose an insignificant human health and environmental impact risk, they are far superior in performance and quality to the alternative products replacing them.

The CACD membership is also concerned that indiscriminant IRIS-listing of copper may also sound a false alarm with a very real significant potential to adversely impact the use of safe copper pigment compounds in the plastics processing industry. Copper is a basic building block in phthalocyanine blue and phthalocyanine green pigments used extensively throughout the color concentrate and plastics procession industries. These pigments are approved and listed by the U. S. Food and Drug Administration (FDA) in Title 21 of the Code of Federal Regulations (21 CFR), Section 178.3297 - Colorants for Polymers for use in food contact applications. These pigments are also listed in other sections of 21 CFR for use in medical devices, drugs, and cosmetics product applications. It should also important to note that copper phthalocyanine pigments, C. I. Pigment Blue 15, Pigment Green 7 and C. I. Pigment Green 36 were removed from the EPA SARA Title III Form R reportable chemicals list in 1992. To include these copper compounds in a general listing for a copper category classification would indeed send a confusing message to plastics industry employees and the consumer.

Crystalline Silica, a component of diatomaceous earth used throughout the plastics industry for physical attributes which improve the use and handling of various plastics, is listed as a probable carcinogen by IARC. This conclusion was based upon animal studies and epidemiological studies that were considered limited for making such a determination. To date, OSHA and NTP have not listed this substance as a potential human carcinogen. CACD recognizes that inhalation of crystalline silica over a long period of time may result in silicosis (a non-carcinogenic lung disease). However, the IRIS evaluation should also consider the safety performance of the industries required to handle this material and the consumer that benefits from use of the safe products that may contain this substance. There is no evidence that diatomaceous earth causes cancer, indicative of the fact that there are no known reported cases of cancer for among those in the mining and processing industry. Once incorporated into the plastic matrix, exposure by inhalation will not occur. To label products containing crystalline silica may alarm consumers unnecessarily.

Styrene monomer, a substance of concern, is a starting component of many varieties of plastics used in food packaging, home appliances, thermal insulation, etc. Again, CACD's primary concern is that consumers will react negatively to various polymers containing styrene in the description where labeling may be required. Styrene monomer content in styrene polymers is stringently regulated under FDA provisions contained in 21 CFR. These polymers may only contain trace quantities of residual monomer encapsulated within the plastic matrix. Due to high molecular weight of polystyrene for instance, (>1000) bio-concentration should not be a significant factor of concern.

Zinc compounds include zinc stearate, another product used widely throughout the plastics processing industry. Zinc stearate is commonly used in food packaging as a stabilizer and/or lubricant and in cosmetics as a lubricant. FDA has also approved the use of zinc stearate as a nutrient in foods. CACD believes the FDA evaluations and approvals associated with this form of zinc clearly demonstrate the need to evaluate the potential health risk of individual compounds versus a category classification. We also feel that IRIS listing of an all encompassing "zinc compounds" category may lead to unnecessary concern by consumers of plastics products containing safe zinc compounds.

IV. SUMMARY

CACD believes it is crucial that the philosophy of sound science be adhered to when evaluating chemicals for inclusion on hazard lists. Chemicals and various compounds should be evaluated individually rather than lumping them in categories which can have the impact of unnecessarily alarming or inflaming the consumer. We also believe that it is in the best interest of the consumer to educate them concerning hazardous chemicals by listing only those chemicals or substances that are known to be hazardous based upon sound scientific evidence. Inclusion of chemicals within a hazard category when no information exists or available information indicates individual compounds within that category to be safe detracts industrial employees and the ultimate consumer from recognizing true hazards and taking proper precautions when and where they are truly warranted. CACD certainly hopes the IRIS Program will take this into consideration when proceeding with the listing of hazardous chemicals.

Respectfully submitted,