usually something can be found near a source in greater concentrations
exposure_to_liquid_phosgene is not exposure_to_phosgene. source is not facility. fish is source_of_protein. source_materials is source. find_inside is not more_controlled_environment. source is facility. fish is not source_of_protein. source_materials is not source. presence is proximity. level_of_exposure is not scalar_quantity.