In this definitive review, Francoiçe Brucker-Davis assembles literature up to 1997 from laboratory experiments, wildlife observations and human epidemiology on possible thyroid disruption by a diversity of chemicals, including DDT, amitrole, thiocarbamates, polyhalogenated hydrocarbons (e.g., PCBs), phenol derivatives and phthalates.

She begins her review by observing that it is vitally important to distinguish between potential impacts on fully-grown individuals vs. impacts via exposure in utero. This is because the thyroid gland in adults is able, within reason, to compensate for mild or moderate disruption (e.g., caused by hyperplasia or goiter). In contrast, the fetus in the womb is highly sensitive to alterations in thyroid hormones, especially its developing brain.

A table compiled by Brucker-Davis summarizes data on over 90 chemicals known to be thyroid disruptors (from laboratory experiments in animals in vitro). It turns out that only a tiny fraction of the 70,000+ chemicals in commercial use have been tested for thyroid activity, even fewer for transgenerational effects examining the consequences of exposure in the womb.

She classifies the main mechanisms of action by which thryoid disruption occurs into four specific categories--thryoid hormone synthesis, transport, metabolism, and tumor--and a catch-all "other." Most of the main synthetic chemicals influence the thyroid system via multiple mechanisms.

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