Thyroiditis

A goiter is any visible enlargement of the thyroid gland.

The thyroid gland, straddling the trachea (windpipe), produces thyroxin, a hormone that regulates the metabolic activity of the body. The thyroid is controlled by the pituitary gland, which secretes thyroid stimulating hormone (TSH) in response to the amount of thyroxin it finds in the blood. TSH increases the amount of thyroxin secreted by the thyroid and also causes the thyroid gland to grow.

"Perchlorate is well known as a major component in rocket fuel, but the chemical also forms naturally. In sufficient amounts, perchlorate disrupts the thyroid by inhibiting the uptake of iodide, an essential component of thyroid hormones."