The current research presents a pilot study of a new application for a hydrophilic biopolymer to stabilize loose sand backfills under dry and wet conditions. Ethyl cellulose (EC) biopolymer is mixed with clean sand in concentrations of 1% and 2%, by weight. The unconfined compressive strength of the EC-treated sand ranged from 1.16 to 3.38 MPa. Compared to sand treated with similar concentration of traditional xanthan and guar biopolymers, the compressive strength is higher, and the collapse potential is much lower. The EC-treated sand is insoluble in water and the strength is unaffected by soaking in water.