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For Immediate Release: April 27, 2005                                        


HONOLULU - The Environmental Protection Agency (EPA) yesterday approved an emergency exemption requested by the Hawaii Department of Agriculture (HDOA) to allow the use of calcium hydroxide (CA(OH)2), commonly known as hydrated lime, to control coqui frog infestations in Hawaii.  This exemption allows nurseries, property owners and government agencies to use hydrated lime in outdoor nurseries, residential areas, resorts and hotels, parks, forest habitats and natural areas to control coqui frogs and their slightly quieter cousins, the greenhouse frogs.  Citric acid was already on a list of exempted chemicals that could be used for pest control; however, citric acid is roughly 10 times more expensive to use than hydrated lime and the cost factor has been restrictive for many nurseries and property owners.

"Obtaining this exemption from EPA to use hydrated lime is a major development in the fight against coqui infestations," said Sandra Lee Kunimoto, Chairperson of the Hawaii Board of Agriculture.  "This product is as effective as citric acid, but much cheaper and readily available as it is commonly used by farmers and home gardeners to enrich the soil."

The exemption by EPA expires in three years, during which time HDOA is required to prepare yearly interim reports and a final report summarizing the results of the use of hydrated lime. EPA indicated that this is the first time that anyone has sought the use of hydrated lime for such purpose under the emergency program section of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

EPA allows treatment using a 97 percent powder formulation of hydrated lime as a dust or in a three percent solution for spraying.  In granting the exemption, EPA requires that HDOA create a product label detailing the conditions under which hydrated lime may be used, which include the following:

  • Not be applied to food crops;
  • A precautionary statement that it is harmful if swallowed;
  • Not be used in areas that were recently treated with ammonium-containing fertilizers, which may react with the lime and release ammonia.
  • Not be applied to areas where children play or congregate;
  • Not be applied to trees to avoid the potential for subsequent dripping of the chemical on people or property, such as automobiles;
  • Applicators must be wear protective clothing, chemical-resistant gloves and protective eyewear and approved respirators;
  • For non-agricultural uses, such as around homes, persons other than the applicator are prohibited from entering the treated area until the spray has dried.

Those wishing to use hydrated lime for coqui control will be required to submit to the dealer selling the product an "Applicator Authorization Form," which may be obtained from the dealer or from HDOA's Pesticides Branch.  Although the form is required, applicators are not required to be certified by HDOA. The application will also be available on the department's website at: 

HDOA reminds the public to follow all label directions when using any pesticide and to be careful to minimize exposure to themselves, their families and neighbors.

For information on how to safely use pesticides, call the HDOA office on your island:

            Oahu -             973-9401
            Big Island -      974-4140
            Maui County -  873-3555
            Kauai -             274-3069


To download forms required to use hydrated lime, click here.

Media contact:

Janelle Saneishi
Public Information Officer
Hawaii Department of Agriculture
Phone: (808) 973-9560
To E-mail, click here