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Publication #PI-91

Pesticide Toxicity Profile: Boric Acid1

Frederick M. Fishel2

This document provides a general overview of human toxicity, provides a listing of laboratory animal and wildlife toxicities and a cross reference of chemical, common and trade names of boric acid insecticides registered for use in Florida.

General

Pesticide products registered for insecticide use in Florida containing boric acid are primarily used for control of ants and cockroaches. They act as stomach poisons and desiccants as they abrade the wax from an insect exoskeleton. Several products are applied as wood treatments for preservation and protection against termites. They are labeled for a wide range of sites, both agricultural and nonagricultural. Many formulations are commercially available, including baits, dusts, powders, liquids, and impregnated materials. The basic element of boric acid is boron, and it is found in the envirment and is an essential nutrient for plants and many organisms. In the U.S., boric acid was first registered as a pesticide in 1948. There are currently more than 100 products registered for use in Florida. EPA has determined that—because of its low toxicity and natural occurrence—boric acid should be exempted from the requirement of a tolerance (maximum residue limit) for all raw agricultural commodities. Because one of its uses is as a crack and crevice treatment in food and feed handling establishments, the potential exists—although its unlikely—for residues to occur in food. For this reason, EPA is establishing food and feed additive tolerances for boric acid.

Toxicity

Boric acid generally has moderate acute toxicity, and it has been placed in Toxicity Category III for most acute effects, including oral and dermal toxicity, and eye and skin irritation. Most poisonings by boric acid have occurred in connection with its former use as a local antiseptic applied to irritated skin, burns, or wounds, or from mistakenly including it in feeding formula for babies. However, children have also ingested the compressed tablets targeting cockroach control. The fatal dose is thought to be 2,000–3,000 mg for infants, 5,000–6,000 mg for children, and 15,000–20,000 mg for adults. EPA has classified boric acid as a “Group E” carcinogen, indicating that it shows “evidence of noncarcinogenicity” for humans. Boric acid materials scattered on the floors of homes present a hazard to children. Its frequent use for cockroach control increases access for ingestion. Chronic ingestion is more likely to cause significant toxicity than acute exposure. The toxins are absorbed by the gut and abraded or burned skin but not intact skin. The kidneys efficiently excrete these compounds, and the residence half-life in humans averages 13 hours. Symptoms include nausea, persistent vomiting, abdominal pain, and diarrhea. In severe poisonings, a red skin rash affecting palms, soles, buttocks, and scrotum has been reported. EPA's concerns regarding risks to birds, fish, and wildlife are minimal. Mammalian toxicities for boric acid are shown in Table 1. Table 2 lists the toxicities to wildlife by the common name of the pesticide. Table 3 provides a cross listing of many of the trade names that these products are registered and sold by in Florida.

Additional Information

  • Crop Protection Handbook. 2014. vol. 100. Willoughby, Ohio: Meister Publishing Co. http://www.meistermedia.com/publications/handbook.html.

  • Nesheim, O.N, F.M. Fishel and M.A. Mossler. 2005. Toxicity of Pesticides. Gainesville: University of Florida Institute of Food and Agricultural Sciences. http://edis.ifas.ufl.edu/PI008.

  • Reigart, J.R. and J.R. Roberts. 2013. Recognition and management of pesticide poisonings, 6th edition. United States Environmental Protection Agency Publication EPA-735K-13001.

  • Seyler, L.A., et al. 1994. Extension toxicology network (EXTOXNET). Cornell University and Michigan State University. http://extoxnet.orst.edu/index.html. Visited December 2005.

  • Young, E.G., R.P. Smith and O.C. MacIntosh. 1949. Boric Acid as a Poison. Can. Med. Assoc. J.:61:447 – 450.

Tables

Table 1. 

Boric acid mammalian toxicities (mg/kg of body weight).

Common name

Rat oral LD50

Rabbit dermal LD50

Boric acid

3,500

>10,000

Table 2. 

Boric acid wildlife toxicity ranges.

Common name

Bird acute oral LD50 (mg/kg)*

Fish (ppm)**

Bee

Boric acid

PNT

PNT

PNT

*Bird LD50: Practically nontoxic (PNT) = >2,000; slightly toxic (ST) = 501–2,000; moderately toxic (MT) = 51–500; highly toxic (HT) = 10–50; very highly toxic (VHT) = <10.

**Fish LC50: PNT = >100; ST = 10–100; MT = 1 – 10; HT = 0.1–1; VHT = <0.1.

Bee: HT = highly toxic (kills upon contact as well as residues); MT = moderately toxic (kills if applied over bees); PNT = relatively nontoxic (relatively few precautions necessary).

Table 3. 

Cross reference list of common, trade and chemical names of boric acid products.

Common name

Trade names*

Chemical name

Boric acid

Boric acid, CB, Drax, Eco, Hot Shot, many others

Boric acid, borax, sodium polyborate, sodium tetraborate, many other forms of boron

*Does not include manufacturers' prepackaged mixtures.

Footnotes

1.

This document is PI-91, one of a series of the Pesticide Information Office, UF/IFAS Extension. Original publication date December 2005. Revised April 2014. Reviewed April 2014. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Frederick M. Fishel, professor, Agronomy Department, and director, Pesticide Information Office; UF/IFAS Extension Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. Use pesticides safely. Read and follow directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.