ENDOCRINE DISRUPTER INFORMATION

Styrene has not been shown to be an endocrine modulator or disrupter.

Attention has focused in recent years on chemicals as potential endocrine disrupters (also referred to as endocrine modulators or estrogen mimics). The inclusion of "styrenes" in early lists of chemicals identified as potential endocrine disrupters led to the appearance of styrene monomer on other such lists. In fact, styrene monomer has been shown to be non-estrogenic when tested against the currently accepted E-screen assay. A limited number of studies have suggested an effect on pituitary gland secretion of prolactin (hyperprolactinemia), which can be associated with menstrual dysfunction. However, these studies are few in number, have serious limitations, and have not been replicated. Dr. Nigel Brown (see previous section) also has reviewed these studies and notes that, collectively, the available data on styrene do not support a conclusion that styrene acts as an endocrine modulator or disrupter.

SIRC has assembled a comprehensive review of the available relevant science on styrene. This information is being shared with regulatory agencies and other groups working to identify endocrine concerns, to ensure that styrene is not inappropriately linked with this issue. For example, the Illinois Environmental Protection Agency (IEPA) Scientific Issues Forum," IEPA concluded: "Based on the weight of the available data, styrene is of low concern as a potential endocrine disrupter. Unless additional evidence to the contrary emerges, IEPA will focus its continuing activities regarding endocrine disrupters on priority chemicals. In the event that the Endocrine Disrupter Strategy is revised or reissued, IEPA would no longer include the chemical styrene as a 'probable' endocrine disrupter."

The U.S. EPA currently is implementing an endocrine disrupter screening and testing program, and will be refining its list of chemicals to be screened for their potential to act as endocrine disrupters. However, EPA has specifically noted that inclusion of a chemical on that list should not be considered an indication that the chemical is an endocrine disrupter. For that program, EPA's current definition of endocrine disrupters applies to substances that are estrogenic or anti-estrogenic, androgenic or anti-androgenic, or which affect the thyroid. Based on this definition, styrene would not be considered an endocrine disrupter.

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