Lonza Group Ltd., a leading supplier to the pharmaceutical, healthcare and life science industries, and Arch Chemicals Inc., a global biocides company, have signed an agreement in which Lonza will buy 100 percent of Arch Chemicals’ outstanding shares of common stock at a price of $47.20 per share in cash, an enterprise value of $1.4 billion.

BASEL, Switzerland/NORWALK, CT – Lonza Group Ltd., a leading supplier to the pharmaceutical, healthcare and life science industries, and Arch Chemicals Inc., a global biocides company, have signed an agreement in which Lonza will buy 100 percent of Arch Chemicals’ outstanding shares of common stock at a price of $47.20 per share in cash, an enterprise value of $1.4 billion.

Lonza’s cash offer is subject to customary conditions including the tendering of more than two-thirds of Arch Chemicals’ outstanding shares of common stock and clearance from antitrust regulatory authorities. Lonza expects to start the tender offer by July 15, 2011, and to complete the tender offer later in 2011.

Upon completion of the transaction, Lonza will have the world’s leading microbial-control business with 2010 pro-forma sales in this life science market of approximately $1.6 billion. Customers, as a result, will have in Lonza a complete solutions provider for their microbial control needs, and the new business will be ideally positioned to increase R&D and product development spending across its broader product portfolio. Lonza will offer this complementary range of products and actives to a broader range of customers in both established and emerging markets. The hygiene, water treatment, materials protection and personal care segments are expected to be the key growth sectors for the combined business. The combined business will also have a broad line-up of regulatory approved microbial-control active ingredients, which will allow Lonza to bring to market new microbial-control formulations and thereby grow revenues across the portfolio.

Headquartered in Norwalk, CT, Arch Chemicals has 23 primary manufacturing and research facilities around the world and currently employs approximately 3,000 people.