Science, Health and Safety Research - American Chemistry Council

Silicones are among the world’s most important and adaptable materials, used in thousands of products and applications – from health care and personal care to electronics, transportation, construction, and energy. The backbone of silicon and oxygen atoms is the foundation of silicone chemistry and allows for the formation of siloxanes. Siloxanes are raw materials based on silicon, oxygen, hydrogen, and carbon and are the critical building blocks used to make silicone products.

Siloxanes, including the cyclic siloxanes octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) are among the most extensively studied materials used in consumer and industrial applications today. A host of independent scientists and expert scientific panels have confirmed siloxanes safety both for human health and the environment.

As part of the Silicones Industry’s commitment to the safety of its products and its sound product stewardship practices, the Industry has proactively conducted several siloxane modelling and monitoring initiatives. Computer models that can estimate a chemical’s physical-chemical properties and potential environmental fate and concentration are important tools for academics, industry, and regulators. Each of the siloxane materials have unique physical-chemical properties that differ significantly from the traditional organic chemicals for which most computer modelling programs have been developed. Thus, the Silicones Industry has collaborated with modelling experts around the world to customize the input parameters of these models based on the properties of the chemical being modelled.

Monitoring Initiatives

Industry and government-initiated environmental monitoring programs have produced a robust data set that demonstrates that:

Siloxanes pose negligible or no risk to the environment
No regulatory restrictions are warranted

Global governments are using real-world data to drive chemical assessments. For example, Environment Canada reviewed the scientific data and environmental monitoring results available for D4 and determined that no restrictions were needed on product use or product concentration limits for D4 in any application. Canada’s Minister of the Environment also ruled that no regulatory restrictions on the siloxane known as D5 need to be imposed after it was found by an independent panel of expert toxicologists to pose no risk to the environment now, nor should it pose any risk in the future. Environment Canada also found that D6 did not meet the criteria for listing as a toxic chemical under the Canadian Environmental Protection Act (CEPA) regulation.

Australia reviewed the scientific data and monitoring results available for D4, D5, and D6. The conclusions reached by their evaluation was in agreement with Canada’s assessment and risk management decisions for these three materials.

Global Environmental Monitoring Initiatives

The Silicones Industry has committed to several environmental monitoring programs aimed at measuring concentrations of siloxanes around the world to customize and validate these models. The Silicones Environmental Monitoring Initiative includes:

Long-term monitoring for D4, D5, and D6 in surface sediments and aquatic organisms to determine if concentrations are stable or changing over time
Evaluating levels of silicone materials in media from wastewater treatment plants (WWTP) and the aquatic environments receiving direct WWTP effluent

The results of this continuous research and testing demonstrate the safety of silicones in their diverse and important applications.

Real World Global Monitoring Data Demonstrate Siloxanes Pose Negligible Risk to Environment

The silicones industry, independent scientific panels, and government authorities in several world regions committed significant resources to better understand the environmental presence and behavior of siloxanes used to make silicones. These siloxanes are known as octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6).

Industry and government-initiated environmental monitoring programs have produced a robust data set that demonstrates that:

Siloxanes pose little or no risk to the environment
No regulatory restrictions are warranted

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