The classification used in Public Health Assessment documents to describe sites at which important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.
A formal conclusion category that ATSDR reserves for sites at which, due to the unavailability of critical information, no determination can be made regarding the existence or non-existence of a potential threat to health in the community.
The designation given to sites for which no conclusions about public health hazards can be made because data are lacking.