Unfortunately there is little you can surmise from the lack of a GSLT listing other than that the substance could use a GreenScreen full assessment. It may be that the substance is highly hazardous for one or more health endpoints but has just not yet hit the radar for the authoritative bodies. Or it may be that it has been well studied and is likely safe. Many authoritative bodies only study substances for which they have an indication of potential harm. There are few attempts to affirmatively identify low-hazard substances.