The rise of the on-demand or “gig” economy creates new safety challenges for workers in the growing employment sector and raises questions about how to ensure they are covered if they are injured while working. For instance, the Washington state Department of Labor & Industries in October ordered San Francisco-based delivery service Postmates Inc. to retroactively pay workers compensation premiums for over 3,000 of its couriers in the state, according to documents provided by the department. Postmates, which allows customers to order groceries and other items through an app, considered its couriers to be independent contractors and did not cover them under workers comp.