Dow, Evonik, Wacker Claim Data Shows Silicone Material Safe

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By Pat Rizzuto

There’s no need for the EPA to restrict uses of a silicone material based on new environmental monitoring data, say five producers who provided the information to the agency.

Millions of pounds of the compound, known as D4, are used in making sealants, adhesives, medical tubing, shampoo, and cell phones.

The Dow Chemical Co., Evonik Corp., Momentive Performance Materials Inc., Shin-Etsu Silicones of America, and Wacker Chemical Corp. submitted a package of environmental monitoring data for octamethylcyclotetrasiloxane, also known as D4 (CAS No. 556-67-2). The manufacturers gave the environmental monitoring data to the Environmental Protection Agency Sept. 5 to comply with an enforceable consent agreement they signed in 2014.

U.S. production and imports of D4 increased from 300 million pounds in 2011 to between 750 million and one billion pounds in 2015, according to information these and other chemical companies reported to the EPA.

Uses Restricted in Europe

D4 is classified in the European Union as reprotoxic and harmful to aquatic life. The EU restricts some uses of D4 and another silicone, decamethylcyclopentasiloxane (D5; CAS No. 541-02-6). The European Chemicals Agency is considering restricting those chemicals’ use in skin products, tissues, and wipes.

The EPA isn’t considering any restrictions now, but D4 is one of the chemicals the EPA has teed up for possible risk assessment. The Toxic Substances Control Act requires the EPA to consider hazard and exposure information as it decides whether a chemical poses sufficient risk to warrant regulation.

The U.S. data show no regulatory restrictions are needed, Karluss Thomas, senior silicone director at the American Chemistry Council, told Bloomberg BNA.

Similar monitoring data convinced Environment Canada that environmental concentrations of D4 were so low that no regulations were needed to control uses of the chemical, according to conclusions it announced in 2012. Instead, Environment Canada required industrial facilities that manufacture or use D4 to prepare and implement pollution prevention plans.Australia has a pending assessment of D4, Thomas said. The new data may be relevant to that assessment if Australia decides the wastewater treatment facilities there are sufficiently similar to those monitored in the U.S., he said.

Broad Uses

More than 99 percent of D4 is used to make silicone polymers, Thomas said. Those heat resistant, flexible polymers are used to make products including:

  •  medical tubes such as drug delivery systems and heart pacemakers,
  •  sealants, adhesives and coatings for concrete, glass, granite, steel and plastic building materials,
  •  cake pans, muffin molds, and baking mats,
  •  shampoos and conditioners, and
  •  cell phones and laptops.

$5 Million Research Effort

The Silicones Environmental, Health, and Safety Center—managed by the American Chemistry Council—measured concentrations of D4 in wastewater, surface water, and sediment from 14 sites in Carrollton, Ky.; Waterford, N.Y.; Sistersville, W. Va.; and Adrian, Mich.

In total, the industry group invested more than $5 million in the D4 research. The data will be made public by the EPA, which did not immediately respond to questions about the information.

The companies measured D4 levels headed to and from their own on-site wastewater treatment facilities, in surface waters, and from treated waters processed by utilities receiving industrial waste water, Thomas said. The companies also measured concentrations in two fish species and one worm-like animal that lives in sediment, he said.

Generating exposure data can be expensive, Thomas acknowledged: the D4 environmental monitoring data package cost a lot more than the $1.2 million originally estimated. But, the center maintains the real value of the data is that it allows the EPA to use actual environmental measurements rather than projections calculated by computer models reliant on assumptions, he said.

Computer models largely are based on information derived from carbon-based chemicals, Thomas said.

“Silicone chemistry is fundamentally different from carbon chemistry,” Thomas said. “Having real world monitoring information is such a critical piece of the evaluation.”

To contact the reporter on this story: Pat Rizzuto in Washington at

To contact the editor responsible for this story: Rachael Daigle at

For More Information

Details on the enforceable consent agreement are available at

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