Ecolab, a water, hygiene and energy technologies company, has appointed Michael Larson to its board of directors.

Larson is chief investment officer to Bill Gates and business manager to Cascade Investment. He has been responsible for Gates' non-Microsoft investments as well as the assets of the Bill and Melinda Gates Foundation Trust since 1995. Previously, Larson was with Harris Investment Management, Putnam Investment Management and ARCO. He also serves as a director of AutoNation, Republic Services, Grupo Televisa and Fomento Mexicano Economico.

Larson's appointment increases the size of the board to 15 members.