An early warning system for equipment or processes which can be permanently or temporarily damaged by contaminants coming from air moving equipment, such as a compressor, positioned upstream of air flowing through the equipment. The present invention provides a seal-leak detection arrangement that, when incorporated into air moving equipment, monitors the air passing through the air moving equipment for the presence of contaminants such as lubricant oil, which could damage the equipment downstream. At least one sensor is positioned downstream of a contaminant retaining seal within the air moving equipment. The seal-leak detection arrangement is particular useful when incorporated into systems upstream of a fuel cell.