The Green Spa Network (GSN) has announced the speaker lineup for its fourth annual congress on sustainability being held between 9 and 12 October at Robert Redford's The Sundance Resort near Park City, Utah.

Speakers at this year's event include Robert Zimmer, developer of Sundance and former CEO of Rosewood Hotels; David Oakey, sustainability expert from Interface Corp; and professor Beverly Macy from UCLA who is also a Huffington Post columnist.

The talks will cover topics such as smart design; public relations and marketing; personal care products; the evolution of spas to vitality centers; and social responsibility.

Roberto Aronja, president of GSN and chief executive of Rancho La Puerta, said: "This Congress will mark a milestone in our history. We are bringing together leaders from the worlds of design, tourism, beauty, marketing and health to further advance the causes of healing, wellness and vitality. Our goal is to craft an action plan that benefits consumers, businesses and the planet - underscoring the fact that we are intertwined and interdependent."

GSN is a community of like-minded spas and resource partners made up of more than 80 spas. The association has already produced a Sustainability Assessment Tool to help guide members in evaluating their sustainability commitment and educating them on next steps. For more on information on the GNS conference, click here.