Phthalates (pronounced "thal-ates") are a group of industrial chemicals that add flexibility and resilience to consumer and building products, particularly those made out of polyvinyl chloride (PVC) or vinyl plastic. About 90% of phthalates are used in vinyl, and are widely used in vinyl building products, and many other consumer and commercial products. Phthalate plasticizers are not chemically bound to vinyl, they can leach, migrate or evaporate into indoor air and concentrate in household dust. Building materials such as vinyl flooring and other consumer products containing phthalates can result in human exposure through direct contact and use, indirectly through leaching into other products, or general environmental contamination. Humans are exposed through ingestion, inhalation, and dermal exposure during their whole lifetimes (Heudorf et al).
Many phthalates are hormone-disrupting chemicals that interfere with the production of the male sex hormone, testosterone, which is necessary for proper development and function of the male reproductive organs. Interference with testosterone activity, especially early in life, can have irreversible effects on male reproduction.
Fetal exposure in male animals has been associated with infertility, decreased sperm count, undescended testes, and malformations of the penis and urethra. When combined at low levels, some phthalates can act together to cause similar harm as seen with exposure to just one phthalate at high levels.
Phthalate exposures in humans has been linked to changes in sex hormone levels, altered development of genitals, and low sperm count and quality. Phthalates have also been linked with obesity, reduced female fertility, preterm birth and low birthweight, a worsening of allergy and asthma symptoms, and altered toddler behavior. Other phthalates, like DiDP, have been linked to other types of birth defects.
In its 2008 report, Phthalates and Cumulative Risk Assessment, the National Academy of Sciences (NAS) concluded that there was sufficient evidence that prenatal exposure to seven phthalates caused common adverse effects on male reproductive development in animals, causing what’s known as “phthalate syndrome,” which has many similarities to “testicular dysgenesis syndrome” in humans. The report stated:
“Some phthalates- such as DBP, BBP, DEHP and DINP- are able to disrupt male sexual differentiation by interfering with androgen biosynthesis;” (p.106).
The NAS also cited strong evidence that exposure to a low-dose mixture of five phthalates caused these effects even when exposure to each phthalate individually showed no effect. Because of these additive effects, NAS strongly recommended the use of cumulative risk assessment that considers the effects of all phthalates (and other anti-androgens) together.
A more recent cumulative risk assessment by the Chronic Hazard Advisory Panel (CHAP) of the Consumer Product Safety Commission concluded that 10% of pregnant women and 5% of infants are exposed to unsafe levels of phthalates in U.S. [i] Based on available data, which are incomplete, the CHAP experts concluded that cumulative exposure to five phthalates creates an unacceptable risk of male reproductive toxicity among those pregnant women and babies exposed to the highest levels of phthalates.
According to the EPA’s chemical action plan for phthalates[ii],
“EPA is concerned about phthalates because of their toxicity and the evidence of pervasive human and environmental exposure to these chemicals… 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.
“Phthalate exposures are a potential concern for children’s health. In animal studies, exposure to phthalates during fetal development results in adverse effects on the male reproductive system. The timing of exposure is critical to the severity of effects. The fetus is the most sensitive life stage for male reproductive effects, and pubertal animals show effects at lower doses than those showing effects in adult animals.”
In recent years, a number of studies have found a correlation between phthalates emitted from vinyl building materials such as flooring and asthma:
Phthalates are semi-volatile compounds that are not chemically bound to the product. Therefore, products continuously release phthalates during use and disposal resulting in routine contamination of indoor air, household dust, the food supply, our bodies and the environment.
Human exposure to multiple phthalates is ubiquitous. [xi] The widespread use of phthalates in building materials and consumer products has resulted in nearly universal contamination of people’s bodies with certain phthalates, which have also been measured in breast milk, umbilical cord blood, and amniotic fluid. Ten years of biomonitoring data gathered by the U.S. Centers for Disease Control and Prevention (CDC) shows near universal exposure to most phthalates in a representative sampling of Americans. Women are exposed to higher levels of phthalates than men, and children are more greatly exposed to phthalates than adults.
According to a report published by the US National Academy of Sciences, “Indoor air is another source of exposure to phthalates from a variety of sources, including aerosols generated from polyvinyl chloride household products, such as vinyl flooring…Infants and young children have higher specific respiratory rates than adults (Etzel and Balk 2003; EPA 2006) and thus have potentially higher specific exposures via inhalation. In summary, infants’ and children’s physiology, developmental stages, and age-appropriate behaviors all may increase exposure to phthalates. Consequently, they may be especially vulnerable to phthalate exposures during critical stages of growth and development.”[xii]
Exposures to phthalates in the indoor environment are commonly attributed to accumulation in indoor dust. House dust can be inhaled or ingested. A 2011 study of residents in Albany, NY calculated that house dust could contribute 10-58% of total DEHP exposure.[xiii] A 2014 study using biomonitoring data and modeling estimated that 39% of DEHP levels were attributable to indoor dust ingestion and 14% to inhalation.[xiv]
Although phthalates have a short half-life in the body, they are routinely detected in the body, indicating persistent exposure on a daily basis. Elimination of sources of phthalates should quickly result in significant reductions in human exposure, and indeed this is supported by biomonitoring studies of people before and after a partial ban on certain phthalates.
Regulatory pressure – including bans and reporting – continues to mount against phthalates based on the growing body of credible scientific evidence. At least 41 phthalates are now under regulation by authoritative government agencies in North America and Europe. (The actual number is higher since this includes both individual compounds and commercial mixtures of multiple phthalates). Some regulations include:
Several authoritative evaluations have examined alternatives to phthalates in a variety of flexible vinyl products,[xv] including vinyl flooring,[xvi] wall coverings,[xvii] medical devices,[xviii] and wire and cable.[xix] The U.S. Environmental Protection Agency is currently examining the many functional alternatives to phthalates that are commercially available today. [xx]
A recently published comprehensive assessment by the Healthy Building Network found six phthalate-free alternatives for flexible vinyl building products that are functionally equivalent, commercially available, and safer than DINP in comparison. The report “Phthalate-free Plasticizers in PVC” recommends:
“Due to its overall human health and environmental impacts from manufacturing to disposal, PVC should be a choice of last resort in the selection of building materials. If the use of flexible PVC is unavoidable, two bio-based products – Grindsted Soft-n-Safe (COMGHA) and Polysorb ID 37 (Isosorbide diesters) – are well studied, appear to be the least toxic, and therefore should be preferred over the other plasticizers studied in this assessment.” [xxi]
Although the report gave preference to two biobased alternatives cited above, all six alternatives profiled had a safer environmental health profile than the phthalate DINP.
Safer flooring alternatives that do not contain phthalates such as bio-based linoleum and natural rubber are widely available.
[i] The CHAP applied conventional assumptions from regulatory toxicology to suggest “safe” levels of exposure to each phthalate. Many independent scientists believe a safety threshold may not actually exist because hormones, and chemicals that disrupt hormones, activate the endocrine system at extremely tiny doses. Further, according the 2008 National Academy of Sciences report Science and Decisions, no safe level of exposure likely exists for any chemicals due to wide variation in susceptibility within the human population.
[ii] U.S. Environmental Protection Agency. 2012. Phthalate Action Plan Summary. Online: http://www.epa.gov/oppt/existingchemicals/pubs/actionplans/phthalates.html
[iii] Larsson, M. et al. 2008. Associations between indoor environmental factors and parental- reported autistic spectrum disorders in children 6-8 years of age. Neurotoxicology doi:10.1016/j.neuro.2009.01.011
[iv] Kolarik, B. et al. 2008. The association between phthalates in dust and allergicdiseases among Bulgarian children. Environmental Health Perspectives 116(1): 98-103.
[v] Bornehag et al. 2002. Dampness in buildings and health. Dampness at home as a risk factor for symptoms among 10,851 Swedish children. (DBH-STEP 1). SP Swedish National Testing and Research Institute and the International Centre for Indoor Environment and Energy, Technical University of Denmark Karlstad University, Sweden.
[vi] Norbäck D. et al. 2000. Asthma symptoms in relation to measured building dampness in upper concrete floor construction, and 2-ethyl-1-hexanol in indoor air. The International Journal of Tuberculosis and Lung Disease Volume 4, Number 11, pp. 1016-1025(10), International Union Against Tuberculosis and Lung Disease.
[vii] Tuomainen, A., Seuri, M., and A. Sieppi. 2004. Indoor air quality and health problems associated with damp floor coverings in an office building. International Archives of Occupational and Environmental Health 77(3): 222-226.
[viii] Jaakkola, J.J.K., Ieromnimon, A. and M.S. Jaakkola. 2006. Interior surface materials and asthma in adults: a population-based incident case-control study. American Journal of Epidemiology 164(8): 742–749.
[ix] Huan Shu, Bo A. Jönsson, Malin Larsson, Eewa Nånberg, and Carl-Gustaf Bornehag. 2013. PVC-flooring at home and development of asthma among young children in Sweden, a 10-year follow-up. International Journal of Indoor Environment and Health. http://dx.doi.org/10.1111/ina.12074
[x] Whyatt RM, Perzanowski MS, Just AC, Rundle AG, Donohue KM, Calafat AM, Hoepner LA, Perera FP, Miller RL. 2014. Asthma in inner-city children at 5–11 years of age and prenatal exposure to phthalates: the Columbia Center for Children’s Environmental Health Cohort. Environ Health Perspect 122:1141–1146; http://dx.doi.org/10.1289/ehp.1307670
[xi] U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Fourth National Report on Human Exposure to Environment Chemicals, Updated Tables, August 2014. See Phthalate and Phthalate Alternative Metabolites, pp. 242-293. http://www.cdc.gov/exposurereport/pdf/fourthreport_updatedtables_aug2014.pdf.
[xiii] Guo, Y and Kannan, K, (2011). ‘Comparative assessment of human exposure to phthalate esters from house dust in China and the United States’. Environmental Science & Technology, 45: pp 3788-3794.
[xiv] Shin, H, McKone, T, and Bennett, D, (2014). ‘Attributing population-scale human exposure to various source categories: merging exposure models and biomonitoring data’. Environment International, 70: pp 183-191.
[xv] Lowell Center for Sustainable Production, University of Massachusetts Lowell, Phthalates and Their Alternatives: Health and Environmental Concerns, January 2011. See http://www.sustainableproduction.org/downloads/PhthalateAlternatives-January2011.pdf.
[xvi] Sarah Lott, Healthy Building Network, Phthalate-free Plasticizers in PVC, September 2014. See http://healthybuilding.net/uploads/files/phthalate-free-plasticizers-in-pvc.pdf.
[xvii] Massachusetts Toxics Use Reduction Institute, Five Chemicals Alternatives Assessment Study, Chapter 7, DEHP, June 2006. See http://www.turi.org/TURI_Publications/TURI_Methods_Policy_Reports/Five_Chemicals_Alternatives_Assessment_Study._2006.
[xviii] Joel Tickner, Lowell Center for Sustainable Production, University of Massachusetts Lowell, The Use of Di-2ethylhexyl-Phthalate in PVC Medical Devices: Exposure, Toxicity and Alternatives, 1999. See http://www.sustainableproduction.org/downloads/DEHP%20Full%20Text.pdf.
[xix] Green Chemistry & Commerce Council, Chemical Hazard Assessments of Alternative Plasticizers for Wire & Cable Applications, June 2013. See http://www.greenchemistryandcommerce.org/assets/media/images/Publications/Pilot%20Project%20Full%20Report%20Oct%202%20-%20final.pdf.
[xx] U.S. Environmental Protection Agency, Design for the Environment, Alternatives to Certain Phthalates Partnership. See http://www.epa.gov/dfe/pubs/projects/phthalates/index.html.
[xxi] Sarah Lott, Healthy Building Network, Phthalate-free Plasticizers in PVC, September 2014. See http://healthybuilding.net/uploads/files/phthalate-free-plasticizers-in-pvc.pdf.