Nontoxic materials are not considered to be harmful or destructive to human health. It is to be noted that at some level, every substance is toxic. Therefore the toxicity must be evaluated in terms of quantity of material. If the quantity of a substance that causes harm is less, its toxicity is determined to be higher.
The following is an example of a Federal Statute defining Non toxic Materials:
Nontoxic materials means “materials for product water contact surfaces utilized in the transporting, processing, storing, and packaging of bottled drinking water, which are free of substances which may render the water injurious to health or which may adversely affect the flavor, color, odor, or bacteriological quality of the water.” [21 CFR 129.3; Title 21-Food And Drugs; Chapter I-Food And Drug Administration, Department Of Health And Human Services; Subchapter B-Food For Human Consumption; Part 129-Processing And Bottling Of Bottled Drinking Water; Subpart A-General Provisions]