Phthalate Background & Hazards

This is one of a series of articles on phthalates. The following are others in the series. If the link is not active, it means that the article is in progress but not finished.


Phthlates are a class of chemicals made from petroleum and added to a vast number of everyday products (

They are found in plastics to provide softness, flexibility, transparency, durability, and longevity. In addition, they are added to many products — especially fragrances in cosmetics, perfumes and lotions, laundry detergents — because they are a “carrier” of fragrance molecules and make those fragrances last longer.

According to government, university and health-care organizations (referenced below), phthalates pose risks to the health of both children and adults:

Phthalates can affect hormone (testosterone) concentrations and growth/development:

In studies using animals, phthalate exposure when the fetus is developing can increase the risk of:

  • Problems with male reproductive organs
  • Decreased birth weight

In children, scientists have observed that phthalate exposures may place the developing fetus at increased risk

  • Changes in male reproductive organs, like hypospadias (positional change of the opening on the penis)
  • Changes in reproductive hormones
  • Increased allergies, runny nose, and eczema

In adults, phthalates may be associated with changes in sperm quality.

Source for the previous hazard summary: “Phthalates and Bisphenol A”  from the Pediatric Environmental Health Specialty Units. Reference link from the National Institutes of Health.

Additional Hazard Assessments From The University of Michigan

The following is a direct excerpt, edited to avoid over-technical language. Deletions are not noted. Comments and additions are [in brackets]. The original document can be found at this link.

Animal Data [very few human studies have been done]

  • The different phthalates vary in their ability to produce the following effects in animal studies:
  1. testicular injury,
  2. liver injury,
  3. liver cancer,
  4. anti-androgenic activity,
  5. teratogenicity [developmental disorders usually relating to embryos and fetuses].
  • In-Vitro [lab equipment)] experiments: BBP and DBP are oestrogenic [act like artificial estrogen which can accelerate growth] in breast cancer cell lines. BBP can also act as an anti-androgen [anti-male hormone].
  • In-Vivo [in live animals] experiments: Research at the Chemical Industry Institute of Toxicology confirmed that DBP does damage the reproductive system of male rats at low exposures, Action disrupts the androgen system, not imitiating the oestrogen. These results demonstrate DBP to be an endocrine disrupter.
  • Animal experiments indicate that MEHP, the metabolite of DEHP can irritate lungs.
  • DEHP is toxic to the developing fetus. The studies documenting these effects range from large studies involving hundreds of animals, to smaller ones with few animals, as well as cell culture studies, and case reports in humans. While most of these effects have been observed in laboratory animals at high doses, in some cases these doses were close to those that might be experienced by individuals undergoing medical treatment. For some adverse effects, such as testicular toxicity, the developing organism appears to be much more sensitive (greater toxicity and irreversibility of effect) than the adult. It is unclear whether a threshold for adverse effects exists.

Trustworthy Resources For Digging Deeper

There are tens of thousands of hazard assessments available on the web.

Some are very old, some only cover a small range of risks and phthalates, and many are biased studies from the chemical industry.

The following will be a growing set of credible and trustworthy links based on well-designed, published, peer-reviewed science conducted by experts who have no conflicts of interest and no stake in slanting science one way or another.

Also in the works is a more comprehensive list of scientific studies  for those Interested in and capable of digging into organic chemistry, molecular biology, epigenetics and other deep science. When that resource goes live, it will be at: Phthalate Research: Peer-ReviewedScientific Studies

 What’s With All The Abbreviations?

There are scores of different phthalate compounds. Eight of the most common have received most scrutiny and are commonly referred to by their abbreviations (in bold) to avoid tongue-tangling chem-speak.

The EPA’s Phthalates Action Plan (PDF) focuses on:

  1. dibutyl phthalate (DBP),
  2. diisobutyl phthalate (DIBP),
  3. butyl benzyl phthalate (BBP),
  4. di-n-pentyl phthalate (DnPP),
  5. di (2-ethylhexyl) phthalate (DEHP),
  6. di-n-octyl phthalate (DnOP),
  7. diisononyl phthalate (DINP), and
  8. diisodecyl phthalate (DIDP).

Phthalates-university of minn hazard asessment

FAQ..plasticizer.industry site

Phthalate (wiki)

Harm in Children

Most recent phthalate research so far has focused on its pre-natal and childhood effects. The New Jersey Health Department is one of the most comprehensive and understandable sources for consumer information and is one of the few covering the presence of phthalates in school supplies: (PVC – a major source of school phthalates)

Phthalates harm children’s health and development by interfering with natural hormone functioning and have been linked to birth defects in baby boys, testicular cancer, liver problems, and early onset of puberty in girls – which is a  risk factor for later-life breast cancer.

Government Assessments

National Institutes of Health – ToxTown – Phthalates

Di(2-ethylhexyl) phthalate is listed as “reasonably anticipated to be a human carcinogen” in the Thirteenth Report on Carcinogens published by the National Toxicology Program. 

Current levels of seven phthalates studied by the National Institute of Environmental Health Sciences posed “minimal” concern for causing reproductive effects. However, the National Toxicology Program concluded that high levels of one phthalate, di-n-butyl phthalate, may adversely affect human reproduction or development.

High levels of exposure to di(2-ethylhexyl) phthalate through the use of medical tubing and other plastic devices for feeding, medicating, and assisting the breathing of newborn infants may affect the development of the male reproductive system, according to the National Institute of Environmental Health Sciences.

Environmental Protection Agency – Phthalates

Phthalates are used in many industrial and consumer products, many of which pose potentially high exposure. Phthalates have been detected in food and also measured in humans.

Adverse effects on the development of the reproductive system in male laboratory animals are the most sensitive health outcomes from phthalate exposure. Several studies have shown associations between phthalate exposures and human health, although no causal link has been established. Recent scientific attention has focused on whether the cumulative effect of several phthalates may multiply the reproductive effects in the organism exposed.

Consumer Product Safety Commission – Phthalates

The CPSC’s  Final Report of the CHAP on Phthalates and Phthalate Substitutes states  that:

Although phthalates cause a wide range of toxicities, the most sensitive and most extensively studied is male developmental toxicity in the rat. Specifically, exposing pregnant dams to certain phthalates causes a syndrome indicative of androgen deficiency, referred to as the “phthalate syndrome” in rats.

Exposure results in abnormalities of the developing male reproductive tract structures, the severity and prevalence of which depends on the dose. The phthalate syndrome is characterized by malformations of the epididymis, vas deferens, seminal vesicles, prostate, external genitalia (hypospadias), and by cryptorchidism (undescended testes) as well as by retention of nipples/areolae (sexually dimorphic structures in rodents) and demasculinization of the perineum, resulting in reduced anogenital distance (AGD).

The highest incidence of reproductive tract malformations is observed at higher phthalate dose levels whereas, changes in AGD and nipple/areolae retention are frequently observed at lower phthalate dose levels. Furthermore, phthalates produce this developmental toxicity in male rodents with an age-dependent sensitivity, i.e., with fetuses being more sensitive than neonates, which are, in turn, more sensitive than pubertal and adult animals.

Health Effects in Humans
The phthalate syndrome in rats bears a resemblance to the “testicular dysgenesis syndrome” (TDS) in humans, which includes poor semen quality, testis cancer, cryptorchidism, and hypospadias, and which is hypothesized to have its origins during fetal life. There is a rapidly growing body of epidemiological studies on the association of exposure to phthalates with human health.

Most studies primarily focus on the association of maternal phthalate exposure with male reproductive tract developmental endpoints and neurodevelopmental outcomes. Two of three cohort studies found reduced AGD in male infants in relation to higher maternal urinary concentrations of phthalate metabolites.

Other studies reported associations between reduced AGD and hypospadias, poor sperm quality, or reduced fertility. Seven prospective pregnancy cohort studies and two cross-sectional studies investigated associations of urinary phthalate metabolites with neurological measures in infants and children.

Interestingly, although each publication utilized different neurological tests at different childhood ages, poorer test scores were generally, but not always, associated with higher urinary levels of some phthalates. Other studies found associations between reduced sperm quality and some phthalates in adult males.

Overall, the epidemiological literature suggests that phthalate exposure during gestation may contribute to reduced AGD and neurobehavioral effects in male infants or children. Other limited studies suggest that adult phthalate exposure may be associated with poor sperm quality.

The AGD effects are consistent with the phthalate syndrome in rats. However, it is important to note that the phthalates for which associations were reported were not always consistent and differed across publications. In some cases, adverse effects in humans were associated with diethyl phthalate exposure, although diethyl phthalate does not cause the phthalate syndrome in rats. None of these studies was designed to provide information on the specific sources of phthalates.

Sitting On The Sidelines

Centers For Disease Control – Phthalates

Food & Drug Administration – Phthalates

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