A bill to extend for 3 years the existing temporary suspension of the duty on mixtures of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, magnesium chloride and magnesium nitrate.

Amends the Tariff Schedules of the United States to extend, through December 31, 1990, the suspension of duty on mixtures of 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, magnesium chloride, and magnesium nitrate.