Construction was recently completed on the American Chemical Society office building at 1550 M St. NW. The 12-story structure is located next to the society's headquarters at 1155 16th St. NW.

The project was developed by the John Akridge Development Co. and took 18 months to complete.

The American Chemical Society owns the $15 million building and eventually plans to occupy all of it, said Nancy Enright, a spokeswoman for the group. The society now occupies three floors of the 68,000-square-foot building and is leasing out the rest of the space.

"We needed a little more room," Enright said. The space in the new building will enable the society to bring back to headquarters some employees who had been moved to a temporary location on Massachusetts Avenue, Enright said.

The society's recent growth in membership was also a factor in deciding to build, Enright said. Founded in 1876, the society describes itself as the nation's largest scientific organization. Since the group's current headquarters opened in 1960, membership has grown more than 50 percent. During that same period, the group's Washington staff grew from 200 to 375.

Designed by the Weihe Partnership, 1550 M Street's facade has alternate bands of polished and flame-cut red granite. Granite accents also were used in the building's two-story lobby. Instead of the usual retail space in the lobby area, the first floor of the building includes a conference facility that will be shared by the building's tenants.

Annual lease rates for the project range from $28 to $34 per square foot, according to Tom Wilbur, project manager for Akridge. The building is 58 percent leased.

Omni Construction was general contractor for the project.

In other developments in commercial realty:

The International Trade Commission leased 200,000 square feet at 500 E St. SW from Boston Properties. Boston Properties was leasing agent.

Thulam Eastern, a retail and installation corporation, leased 15,000 square feet at 14200 Sullyfield Cir., Chantilly, from Cambridge Development Corp. Julien J. Studley Inc. was the leasing agent.

Susan Davis Cos., a public relations firm, leased 24,523 square feet at 1146 19th St. NW. from 1146 19th St. Corp. Smithy Braedon represented the tenant and Barrueta and Associates represented the landlord in the transaction.