1. Dilute ethidium bromide to less than 0.5 mg/ml with water.

2. For each 100 ml of ethidium bromide, add 20 ml of freshly prepared 50% (v/v) hypophosphorous acid (H₃PO₂) and 12 ml of freshly prepared 0.5 M sodium nitrite (NaNO₂). Stir the mixture to homogeneity and allow to stand for 20 hours under ambient conditions.

3. Adjust the pH to approximately 7 with sodium bicarbonate.

4. Discard via sanitary sewer.

Decontamination of Ethidium Bromide in Isoamyl Alcohol (Isopentanol) and 1-Butanol

Waste ethidium bromide in these matrices should be collected and disposed of as hazardous waste.