Introduction to phthalates, the “plasticizers”

Phthalates are chemical compounds that support flexibility and durability in a variety of building materials. However, their chemistry makes them prone to leaching from these materials polluting the immediate environment and negatively impacting human, climate, & ecosystem health.

What are Phthalates?

Phthalates enhance the flexibility, resilience and durability of plastics, especially PVC. Building materials are the largest use for PVC making phthalates widely present in the built environment. Phthalates are used in carpet backing, resilient flooring, wall coverings, upholstery textiles, acoustic ceiling surfaces, roof membranes, waterproofing membranes, sealants and caulks, electrical cord insulation. Global demand for plasticizers continues to rise: the estimated global market of Phthalates in 2020 was expected to reach 10 billion USD.

Based on their chemical and physical properties Phthalates can be broadly divided into 2 groups:

1. Low-Molecular-Weight (LMW): These phthalates include those with 3-6 carbon atoms and typically have shorter alkyl chains making them less resistant to migration. LMWs pose higher concerns to human and environmental health because they are more volatile in nature and are more likely to leach. Some examples of LMW Phthalates include:
   1. Dimethyl Phthalates (DMP). Used in Insect repellent, Plastic coatings, & Adhesives
   2. Diethyl Phthalates (DEP). Used in personal care products like perfumes, lotions, toothbrushes
   3. Benzyl Butyl Phthalates (BBP). Used in Vinyl flooring, car interiors, synthetic leather
2. High-Molecular-Weight (HMW): These Phthalates include those with 7 or more carbon atoms increasing their permanency and durability. These have longer alkyl chains and are used primarily on construction and automotive applications. These are less volatile but can leach into environment over time. American Chemistry Council indicates that HMW phthalates poses lower risk to human health at typical exposure level as they are more resistant to extraction, evaporation and migration. Examples include
   1. Diisononyl Phthalate (DINP). Used in flexible PVC products like cables, vinyl floorings, window shades, roofing, pool liners, wall coverings, sealants, toys.
   2. Diisodecyl Phthalate (DIDP). Used in electrical cables, synthetic leather, car interiors, vinyl flooring, roofing, pool liners, wall coverings, Adhesives and sealants.
   3. Di-n-Octyl Phthalate (DNOP). Used in carpet backing, floor tiles, wire insulation, food applications

Why are we concerned about phthalates?

Phthalates are not chemically bound to the materials they are added to making them prone to environmental leaching. Building materials, automotive products and other personal care products can release toxic particles into the air over time, a process known as off-gassing. Concerns related to phthalates include:

Human Health - exposure to phthalates occurs through inhalation, ingestion or dermal contact and it has been linked to various health issues. Phthalates can off-gas into indoor air increasing exposure risks.

1. Endocrine Disruption: Phthalates can interfere with hormonal system impacting the reproductive health and development especially impacting male reproductive toxins.
2. Respiratory issues: Studies suggest phthalates contribute to respiratory disease like asthma and allergic reactions especially in children.
3. Developmental and Neurological effect: Prenatal and early-life exposure to phthalates is associated with hindrance in cognitive and behavioral growth. Pregnant women and infants are especially affected by this.

Social health and Equity: increased risk for underserved populations, unequal access to safe alternatives, and lack of education.

1. Disproportionate impact on vulnerable groups:
   1. Infants are more susceptible to developmental disorders resulting from exposure to phthalates due to behaviors like mouthing objects and contact with toys and teething rings.
   2. Exposure during pregnancy is linked to fetal development issues including endocrine and reproductive system disruptions.
   3. Lower income communities are often closer to industrial facilities, landfills or waste sites where phthalates are more prone to leaching into air, water and land.
2. Occupational Hazards: Workers in manufacturing and construction industries face higher exposure level due to production/use of Phthalates. Inadequate workplace safety measures increase the risk for workers especially in developing regions due to a lack of regulations.
3. Lack of awareness: Limited public knowledge about phthalates in everyday products and their potential health impacts is a challenge to informed decision-making. Complex product labels and lack of multilingual resources hinder vulnerable groups from understanding the risks of phthalates.
4. Global Disparities: Wealthier nations often export phthalate-containing products and waste to developing countries increasing the exposure risk for developing regions battling with fewer resources to manage toxic chemicals.

Ecosystem: risks to natural habitats, food, and water sources.

1. Persistent, bio-accumulative pollutants: Phthalates from plastics, building materials, and industrial waste leach into soil, waterways, and ground water. They persist in the environment for very long durations, especially HMWs, where they cause disruption in the hormonal system of aquatic life leading to reproductive and developmental issues. Microbial communities essential for nutrient cycling and soil health are also disrupted by phthalates contamination which are absorbed by plants over time. Crops irrigated on contaminated soil or water causes bioaccumulation and food chain contamination.
2. Air quality: LMWs evaporate or are dispersed into the air impacting indoor and outdoor air quality. They adhere to household and industrial dust which can reenter the ecosystem through deposition.
3. Waste management challenges: Plastic recycling efforts are complicated by phthalates. Burning phthalates-containing materials can release harmful dioxins and toxic by-products into the air.
4. Microplastic pollution: Phthalates weaken the structure of plastics, accelerating the breakdown into microplastics that accumulate across global ecosystems.

Climate health: risks that accelerate or amplify the impacts of the Climate Crisis.

1. Carbon Embodiment in production: Phthalates are derived from petrochemicals (i.e. fossil fuels). The extraction, refining and processing of oil and natural gases for phthalates emits large quantities of carbon dioxide and methane. Production of phthalates containing materials involve high-energy processing contributing to their carbon footprint.
2. Greenhouse Gas Emissions: Phthalate production emits carbon dioxide CO₂, methane CH₄, and nitrous oxide (N₂O), which are potent Greenhouse gases. The production of PVC (a major user of phthalates) generates approximately 2 kg of CO₂ equivalent per kg of material.

How can architects mitigate the impacts of phthalates in building materials?

Understand common applications in construction

1. Flooring – Widely used for durability and affordability. Helps make floors stain resistant.
2. Sealants and caulks – To maintain elasticity over time
3. Carpet backing and adhesives – Added to adhesives for flexibility and binding properties
4. Insulation and wiring – To increase durability of insulation and make electrical wires pliable. Also to maintain low conductivity and heat resistance.
5. Window shades – To withstand wider temperature differences and improve durability
6. Roofing – To make materials UV resistant, durable and energy efficient
7. Pool liners – To make it weather resistant
8. Wall coverings – To improve longevity and reduce emissions from other chemicals.

Specify alternatives to Phthalates

1. No Phthalate Plasticizers: Innovative technologies like adipates, citrates and bio-based alternatives provide safer options for construction materials. DEHT/DOTP (Di(2-ethylhexyl) Terephthalate) is a phthalate-free plasticizer used in flooring and other products
2. Bio-Based Plasticizers: Derived from renewable sources like soybean oil or castor oil, these are increasingly used in eco-friendly and low-toxicity products.
3. PVC-Free Materials: Opting for alternatives like using natural linoleum. Using ceramic or porcelain tiles that are durable but do not cause harmful emissions. Bamboo or cork flooring which are sustainable.
4. Water based Adhesive and sealants: These alternatives avoid the need for plasticizers and are safer for indoor air quality.
5. Composite Engineered materials: Promote materials that are engineered to avoid the use of phthalates entirely, providing similar performance without health risks.

Specify safer use of phthalates

1. Choose Low-Risk Phthalates: Not all Phthalates have the same level of toxicity. Consult regulatory guidelines.
2. Encapsulate or seal: material coating can reduce the risk of off-gassing or leaching. High-quality coatings on vinyl floors or wall coverings can reduce chemical release into the environment.
3. Air filtration and ventilation: Ensure spaces with phthalate-containing materials are well-ventilated. Incorporate strategies like activated carbon filters or HEPA filters to reduce air contamination
4. Limit use in sensitive areas: Avoid using phthalate-containing materials in spaces where vulnerable populations (e.g., children, pregnant women) spend significant time, such as homes, hospitals, and schools.
5. Test for emissions and compliance: Testing for phthalate levels in indoor environments can ensure levels stay within safe limits.
6. Replace Phthalate-containing materials in areas requiring frequent cleaning or high durability with safer alternatives.

Demand Transparency

1. All material health starts with transparency - require content disclosures like Health Product Declarations (HPDs) for material transparency.
2. Increase awareness, by requesting information about chemical composition in conversation with manufacturers and contractors.
3. Advocate for environmental safeguarding through the promotion of phthalate testing and more accessible information/resources about these chemical groups

Learn more about phthalates below!

https://nchh.org/information-and-evidence/learn-about-healthy-housing/building-products-materials-and-standards/chemicals/

https://www.webmd.com/a-to-z-guides/features/what-are-phthalates

https://www.americanchemistry.com/chemistry-in-america/chemistries/high-phthalates

https://www.americanchemistry.com/industry-groups/high-phthalates

https://www.epa.gov/assessing-and-managing-chemicals-under-tsca/phthalates