Maleic hydrazide (MH) formulations containing 3 pounds per gallon of active ingredient can no longer be manufactured for sale in the United States. However, all 3-pound MH formulations that were manufactured before October, 1981 can be sold until the supply of that formulation is exhausted. MH formulations containing 1.5 or 2.25 pounds of active ingredient (Potassium salt of MH) can still be manufactured and sold in the U.S. for controlling suckers on tobacco.
Atkinson, W. O.; Smiley, Jones H.; and Wallace, Allen, "Sucker Control Chemicals for Use on Burley Tobacco" (1982). Agronomy Notes. 104.