Silicones are among the most extensively studied materials used in consumer and industrial applications today. More than 1,000 studies have been conducted by silicone manufacturers to assess the safety of silicones relative to workers, consumers, the environment and manufacturing processes. The results of this continuous research and testing demonstrate the safety of silicones in their diverse and important applications.
Committed to the responsible use of silicones, the industry continues to evaluate the science behind the material through several rigorous research programs. Research methodologies include computer modeling, laboratory testing, environmental monitoring and other approaches.
ACC Silicones Environmental, Health, and Safety Center research ranges across many different silicone substances, but is concentrated primarily on the most commonly used siloxanes:
- Octamethylcyclotetrasiloxane (D4)
- Decamethylcyclopentasiloxane (D5)
- Dodecamethylcyclohexasiloxane (D6)
- Hexamethyldisiloxane (HMDS)
- Polydimethylsiloxanes (PDMS)
Silicone manufacturers regularly communicate research findings to SEHSC members, customers, government officials and the scientific community.
For more information on Environment and Health Canada’s draft assessment of D4, D5 and D6 under the Chemicals Management Program, click here.
For more information regarding D5 and the California Air Resources Board determination under AB 998, click here.
Octamethylcyclotetrasiloxane (D4) is an odorless, colorless non-oily silicone fluid used primarily to make other silicone materials. During this manufacturing process, virtually all of the material is consumed, with only a tiny amount of D4 remaining. In a small handful of personal care products, D4 can be used as an additive providing certain application-related benefits preferred by consumers.
D4 is one of the most extensively studied chemicals used in consumer applications. Several studies have been conducted assessing the safety of D4 and the data support that D4 is safe when used as intended.
Decamethylcyclopentasiloxane (D5) is an odorless, colorless non-oily siloxane fluid used as an ingredient in personal care products and dry cleaning.
In personal care products, D5 acts as a "carrier," allowing products to spread smoothly and easily, providing a silky, luxurious feel during application. In dry cleaning, D5 carries detergent to clothes and rinses away suspended dirt and oils trapped by the detergent. It does not interact with textiles and, therefore, helps maintain the quality and color of clothes that are dry cleaned.
D5 is among the most extensively studied materials used in consumer and industrial applications. More than 50 studies have been conducted and the data support that D5 is safe when used as intended.
Dodecamethylcyclohexasiloxane (D6) is a clear, odorless, siloxane fluid that is used in some applications including cosmetics, where it provides certain application-related benefits preferred by customers.
D6 has been extensively studied for its safety in consumer and industrial applications and the data indicate that, when used as intended, D6 is safe.
Canada's Challenge to Industry
In 2006, the Canadian government announced their comprehensive strategy for managing chemicals, the Chemicals Management Plan, as a way to gather information on approximately 4,000 of the 23,000 or so materials in commerce in Canada. These substances were categorized for further assessment to determine potential risks to health or the environment. Inclusion in the program did not, in itself, indicate a potential risk, but allowed the Canadian government to gather information—including scientific data that may not have been used in the initial screening—that would help provide a more complete understanding of the health and environmental effects of each material. Several silicone materials were included in this program.
SETAC Workshop Findings
A recent issue of Integrated Environmental Assessment and Management, a journal published by the Society of Environmental Toxicology and Chemistry (SETAC), features a special series of papers generated from the SETAC workshop "Science-Based Guidance and Framework for the Evaluation and Identification of PBTs and POPs."
Persistent, bioaccumulative, and toxic substances (PBTs) and persistent organic pollutants (POPs) are regulated by many regional, national, and global conventions. Despite growing worldwide concerns about contamination and the safety of our food supply, advances in chemistry, information, and other technologies during the past two decades are not being sufficiently applied. As a result, effective guidance for the identification, assessment, and management of these substances is limited and often out-of-date.
Many substances, like the cyclic siloxanes, are inaccurately characterized as PBT substances based on out-of-date scientific screening criteria. However, current science and real-world measurements in the environment demonstrate that these substances are safe for human health and the environment, and should not be classified as PBT.
The articles convey the key elements of the current state of the science, the evolution of scientific understanding, and the challenges for future worldwide regulation of PBT chemicals and POPs. The series is based around the intensive science and regulatory policy deliberations that took place during a SETAC international workshop, held in January 2008. The meeting was the largest gathering of international experts on this issue to date. The views of the participants at that meeting, representing broad international perspectives from academia, government, and industry, will influence science and environmental policy at future international treaty conventions on this topic.
SETAC released the findings of the workshop in its journal Integrated Environmental Assessment and Management (Vol. (5)4: 535-538; October 2009, "Introduction to Special Series: Science-Based Guidance and Framework for the Evaluation and Identification of PBTs and POPs." To learn more about the workshop or to purchase a copy of the journal, visit www.setacjournals.org.