SAFC® Introduces Environmentally-Safe Broad Spectrum Biocide for Medical In Vitro Diagnostics

ST. LOUIS, MO. – June 15, 2010 – SAFC®, a member of the Sigma-Aldrich® Group (NASDAQ: SIAL), today announced the launch of a new, 'ready-to-use' solution-based biocide, ProClin® B-119 (www.safcglobal.com/proclin). This safe and effective biocide designed for challenging formulation conditions works across pH levels 4-12 and temperatures of up to 90 °C to control microorganisms, providing stability and reliability of in vitro Diagnostics (IVD) reagents used in medical testing. ProClin B-119 is formaldehyde-free and has been specifically designed to meet a wider range of pH levels and temperatures than biocides currently on the market.

"ProClin B-119 is valuable for R&D scientists looking for a robust biocide that is safe, efficient and effective for their diagnostics research," said George Crowell, SAFC's Diagnostics Segment Manager. "This addition, offered exclusively through SAFC, extends the Company's diverse product portfolio for the rapidly expanding medical diagnostics market, providing single-point access to a broad range of regulatory compliant and custom manufactured raw materials."

Combining technical and industrial expertise, SAFC provides customers security of supply with over 100,000 raw materials, of which 48,000 are produced in-house, along with the capability of providing customized manufacturing, packaging and comprehensive analytical services.

The foregoing release contains forward-looking statements that can be identified by terminology such as "efficient and effective," "robust," "meet a wider range of pH levels and temperatures than biocides currently on the market," or similar expressions, or by expressed or implied discussions regarding potential future revenues from products derived therefrom. You should not place undue reliance on these statements. Such forward-looking statements reflect the current views of management regarding future events, and involve known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from any future results, performance or achievements expressed or implied by such statements. There can be no guarantee that SAFC's product offer will continue to meet the demands of the diagnostics marketplace. Nor can there be any guarantee that any of its products will achieve any particular levels of revenue in the future. In particular, management's expectations regarding these products could be affected by, among other things, unexpected regulatory actions or delays or government regulation generally; the Company's ability to obtain or maintain patent or other proprietary intellectual property protection; competition in general; government, industry and general public pricing pressures; the impact that the foregoing factors could have on the values attributed to the Company's assets and liabilities as recorded in its consolidated balance sheet, and other risks and factors referred to in Sigma-Aldrich's current Form 10-K on file with the US Securities and Exchange Commission. Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those anticipated, believed, estimated or expected. Sigma- Aldrich is providing the information in this press release as of this date and does not undertake any obligation to update any forward-looking statements contained in this press release as a result of new information, future events or otherwise.

About SAFC: SAFC is the custom manufacturing and services business unit within Sigma-Aldrich that focuses on high-purity inorganics for high technology applications, cell culture products and services for biopharmaceutical manufacturing, biochemical production and the manufacturing of complex, multi-step organic synthesis of APIs and key intermediates. SAFC has manufacturing facilities around the world dedicated to providing manufacturing services for companies requiring a reliable partner to produce their custom manufactured materials. SAFC has four focus areas – SAFC Pharma®, SAFC Supply Solutions®, SAFC Biosciences®, and SAFC Hitech® – and had annual sales of over $600 million in 2009. SAFC is one of the world's 10 largest fine chemical businesses. For more information about SAFC, visit www.safcglobal.com.

About Sigma-Aldrich: Sigma-Aldrich is a leading Life Science and High Technology company. Its biochemical and organic chemical products and kits are used in scientific research, including genomic and proteomic research, biotechnology, pharmaceutical development and as key components in pharmaceutical, diagnostic and other high technology manufacturing. The company has customers in life science companies, university and government institutions, hospitals, and in industry. Over one million scientists and technologists use its products. Sigma-Aldrich operates in 38 countries and has 7,600 employees providing excellent service worldwide. Sigma-Aldrich is committed to Accelerating Customer Success through Innovation and Leadership in Life Science, High Technology and Service. For more information about Sigma-Aldrich, please visit its award-winning Web site at www.sigma-aldrich.com.

Sigma-Aldrich and SAFC are registered trademarks of Sigma-Aldrich Biotechnology L.P. and Sigma-Aldrich Co. ProClin is a registered trademark of Rohm and Haas Chemicals LLC, a wholly owned subsidiary of The Dow Chemical Company.