Arch Chemicals, Inc. Conference Call Announcement

A conference call to review first quarter 2009 results will be held on Tuesday, May 5, 2009, at 11:00 a.m. (ET) by Michael E. Campbell, Chairman, President and CEO; Louis S. Massimo, Executive Vice President and COO and Steven C. Giuliano, Vice President and CFO. Prepared remarks will take about 20 minutes and will be followed by a question and answer period.

Financial and segment information will be released Tuesday morning, May 5, before the market opens. The release will be available on First Call, Business Wire and Dow Jones News Service.

If you wish to participate, please call (888) 724-9493 access number 8825426, at least ten minutes before the call is scheduled to begin. From outside the U.S., please call (913) 905-3216 access number 8825426. The live Webcast of the call can be accessed on the home page of the Company’s Web site: http://www.archchemicals.com; it will be Windows Media Player and RealPlayer compatible.

A replay of the call will be available from 1:00 p.m. on Tuesday May 5, until 6:00 p.m. (ET) on Tuesday, May 12. The replay number is (888) 203-1112, access number 8825426; from outside the U.S., please call (719) 457-0820, access number 8825426.

Headquartered in Norwalk, Connecticut (USA), Arch Chemicals, Inc. (NYSE: ARJ) is a global Biocides company with annual sales of approximately $1.5 billion. Arch and its subsidiaries provide innovative, chemistry-based and related solutions to selectively destroy and control the growth of harmful microbes. The Company’s concentration is in water, hair and skin care products, treated wood, paints and building products and health and hygiene applications. Arch Chemicals operates in two segments: Treatment Products and Performance Products. Together with its subsidiaries, Arch has approximately 3,000 employees and manufacturing and customer-support facilities in North and South America, Europe, Asia, Australia and Africa.