chemical information


Chemical Class:


Found in these people:

Davis Baltz, Lucy Waletsky

Found in these locations:

Berkeley, CA; Pleasantville, NY


Found within many consumer products, phthalates are industrial plasticizers that impart flexibility and resilience to plastic, among other uses. Di-n-octyl phthalate (DOP) is used primarily to produce flexible plastics (CDC 2005). Exposure to DOP occurs through direct use of products containing this chemical, as well as through inhalation of contaminated air (CDC 2005). In the body, DOP is converted primarily to the metabolite, or breakdown product, mono-3-carboxypropyl phthalate (mCPP), and in smaller amounts to mono-n-octyl phthalate (mOP).

In September 2000, scientists from the Centers for Disease Control and Prevention (CDC) conducted the first accurate measurements of human phthalate exposures, and reported finding phthalates in every one of 289 people tested, at surprisingly high levels (Blount 2000). The latest exposure study from CDC indicates that the DOP metabolite mCPP is a widespread contaminant of the human body, while mOP is less common (CDC 2005). Measurements of mCPP in the urine of over 2,500 Americans indicate that women are slightly more exposed than men, and children age 6 to 11 are more exposed than older children and adults (CDC 2005). In a recent study of girls age 6 to 8 spearheaded by Mount Sinai School of Medicine, this particular phthalate metabolite was found in all 90 girls tested (Wolff 2007). The European Union has banned use of some phthalates in cosmetics and other consumer products, in response to concerns about exposure as well as toxicity.

Phthalates are potent toxins to the male reproductive system. High levels of some phthalate metabolites are associated with reduced levels of sperm motility and concentration, and alterations in hormone levels in adult men (Duty 2003, 2004, 2005). A recent study of 134 births found marked differences in the reproductive systems of baby boys whose mothers had the highest phthalate measurements during pregnancy (Swan 2005). A second study indicates that these mothers' phthalate exposures were not extreme, but rather were typical for about one-quarter of all U.S. women (Marsee 2006). Further research documented decreased testosterone levels among baby boys exposed to phthalates in their mother's breast milk (Main 2006). No studies have assessed associations between DOP or its metabolites and human health outcomes in the general population.

Laboratory studies indicate phthalates cause a broad range of birth defects and lifelong reproductive impairments in animals exposed in utero and shortly after birth (Marsman 1995; Wine 1997; Ema 1998; Mylchreest 1998, 1999, 2000; Gray 1999). Phthalate exposures damage the testes, prostate gland, epididymis, penis, and seminal vesicles in laboratory animals (e.g., Mylchreest 1998); most of these effects persist throughout the animal's life. DOP causes thyroid gland toxicity that includes decreased levels of thyroid hormone (thyroxine or T4), and decreased follicle size and colloid density. Other effects include liver toxicity and altered kidney weights. DOP has also been shown to damage cellular organelles, including the mitochondria (ATSDR 1997, CERHR 2000d). Developmental effects include decreased body weight, abnormal sperm and increased incidence of external malformations.

Di-n-octyl phthalate

Used in plastics, adhesives, rubber. Animal studies indicate toxicity to thyroid and liver.

Di-n-octyl phthalate has been found in 2 of the 9 people tested in EWG/Commonweal studies.

Top health concerns for Di-n-octyl phthalate (References)

health concern or target organ weight of evidence
Birth defects and developmental delaysunknown

Results for Di-n-octyl phthalate

in blood serum (lipid weight)

Showing results from EWG/Commonweal Study #1, industrial chemicals and pesticides in adults

EWG/Commonweal results

  • found in 2 of 9 people in the group

found in 2 of 9 people, but not quantified

Detailed toxicity classifications (References)

classification governing entity/references
Birth defects - weight of evidence unknown/unassessedATSDR, CERHR