Use directions on algicide and herbicide labels are designed to protect both the environment and the user from unreasonable risk. The reviewers concluded that the scientific evidence does NOT support the conclusion that 2,4-D causes cancer in humans. 2,4-D belongs to a family of compounds referred to as the phenoxy herbicides. Only products labeled for control of pondweeds can be used legally in ponds. The manufacturer did not renew the aquatic label for simazine products when it expired because of concerns over possible groundwater contamination.
Chemicals can change with time and become unsafe to use.
Only buy the amount of chemical that you need. Pesticides are poisons which can cause serious illness or even death. Placing a pesticide in an unlabeled or mislabeled container could lead to a serious accident. Always follow label instructions. Many aquatic algicides and herbicides are labeled for use by the general public, while others are restricted to certified applicators only.