Mercury (element) used in teething powders for infants. The mercury-containing organohalide merbromin (sometimes sold as Mercurochrome) is still widely used but has been banned in some countries such as the U.S. Mercury and most of its compounds are extremely toxic and must be handled with care; in cases of spills involving mercury (such as from certain thermometers or fluorescent light bulbs), specific cleaning procedures are used to avoid exposure and contain the spill. Protocols call for physically merging smaller droplets on hard surfaces, combining them into a single larger pool for easier removal with an eyedropper, or for gently pushing the spill
Substantial equivalence testing may be conducted, leading to a final safety assessment. Substantial equivalence is the underlying principle in GM food safety assessment for a number of national and international agencies, including the Canadian Food Inspection Agency (CFIA), Japan's Ministry of Health, Labour and Welfare (MHLW), the US Food and Drug Administration (FDA), and the United Nations' Food and Agriculture Organization (FAO) and World Health Organization. The concept of comparing genetically modified foods to traditional foods as a basis for safety assessment was first introduced as a recommendation during the 1990 Joint FAO/WHO Expert Consultation on biotechnology and food safety (a scientific