DENVER (AP) — A Colorado hospital has postponed most of its scheduled surgeries while it resolves an issue with the cleaning of certain surgical instruments.

Porter Adventist Hospital in Denver said in a statement that it was working closely with patients to reschedule surgeries.

Earlier this week, the hospital warned that some of its patients might be at risk of contracting hepatitis B, hepatitis C or HIV because surgical instruments weren't properly cleaned.

Colorado Department of Public Health and Environment officials conducted an additional on-site survey Thursday and noted that while they had not identified any infections caused as a result of the situation. However, the agency says it's still investigating.

Officials say instruments weren't cleaned adequately at Porter Adventist Hospital following orthopedic and spine surgeries between July 21, 2016, and Feb. 20.