Phthalates: Tracking Hidden Chemicals in Plastic

Plastics have been scrutinized for their environmental impacts, but growing concern has emerged around the lesser-known chemical additives blended into plastic products. While materials like polyethylene terephthalate (PET) or polyvinyl chloride (PVC) are well-regulated, additives in plastic products are less controlled, leaving gaps in safety standards. A recent study reported at least 16,000 known chemicals present in plastics, yet only 6% of all compounds are regulated internationally; more than half of these chemicals  have not been studied for safety.

Many of the plastics we’re familiar with today would be unusable without additives. Additives enhance and help engineer the properties of the final plastic, including flexibility, flame resistance, or color. One of the most controversial groups among these additives is phthalates. 

What are phthalates and why do they matter?

Phthalates are commonly used as plasticizers, primarily to transform rigid polymers like PVC into flexible materials that can be used in everything from medical devices to construction materials. Pthalates are also commonly used in consumer products, food packaging, and personal care and household products. However, mounting evidence links phthalates to significant health concerns, particularly reproductive health issues. Agencies, including the FDA, EPA, and some in the European Union, are either restricting or monitoring the use of phthalates while research continues.

Widespread Phthalate Exposure Persists Despite Regulations

A 2019 global review of biomonitoring studies  found that phthalate metabolites—small particles left behind when our bodies break down phthalates (chemicals like DEP, DBP, and DEHP used in plastics and personal care products)—are consistently detected in human urine, with levels reaching tens to hundreds of nanograms per milliliter.

More recent evidence from Southern California demonstrates that both traditional ortho-phthalates (a type of chemical used in plastics and other products) and newer alternatives known as non-ortho-phthalates remain abundant in urban environments. Researchers used innovative silicone wristband monitoring over five days and found alarmingly high total concentrations ranging from 100,000 to 1,000,000 ng/g. Three compounds, DEHP, DiNP, and DEHT, accounted for nearly all exposure measurements (94-97%), highlighting that even with alternatives and regulations, exposure to phthalates additives remains widespread. We have abundant evidence that nearly everyone has been exposed to phthalates. 

Current Exposure to Phthalates and Health Implications

This high and ubiquitous exposure to phthalates is particularly concerning due to the “phthalate syndrome”, explored in the past decades by Dr. Shanna Swan. Phthalate syndrome is a collection of reproductive health impacts linked to prenatal phthalate exposure. Through decades of research culminating in her book “Count Down,” Swan demonstrates how these plastic additives may contribute to declining fertility rates across generations. Her work shows that exposure during critical developmental windows can impact reproductive health later in life for men and women.

Navigating Phthalate Risks for a Safer, Sustainable Plastics Future?

The persistence of phthalates in our environment, despite regulations and industry shifts, underscores the need for a comprehensive perspective on the public health effects of plastics. Some states have restricted certain harmful plastic chemicals. Industries have stepped up as well, by launching initiatives to eliminate unnecessary additives and promote circular economy principles. Also, alternative plasticizers such as DEHT have entered the market. These efforts show promise, but must be accompanied by robust safety assessments. 

As discussions continue around the UN Global Plastic Treaty and other regulatory frameworks, the experience with phthalates offers valuable lessons about the importance of comprehensive chemical assessment, monitoring, and regulation in creating a truly sustainable plastics economy. 

Looking ahead, the phthalate story demonstrates why tracking and understanding chemical additives in plastics is crucial for public health and environmental safety. As this story continues to develop, RTI Innovation Advisors provides our clients the tools and expertise needed to analyze complex supply chains, assess emerging trends, and address the challenges posed by harmful chemical additives in plastics. By identifying risks, evaluating safer alternatives, and aligning with evolving regulations, the Innovation Advisors team enables our clients to make informed decisions that prioritize public health and environmental sustainability.