Kentucky Pesticide Safety Education Program
stacked logs

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Dr. Ric Bessin
Dept. of Entomology
University of Kentucky

Protecting the Environment

It is not only people who can suffer from the careless use or disposal of wood preservatives—your community’s environment also may suffer. Wood preservatives must be toxic in order to kill or repel the fungi, and insects that destroy wood.

Unfortunately, these chemicals are not selective; they can harm non-target organisms. Contaminated runoff can pollute lakes, streams, and wetlands, thereby damaging habitat for fish and wildlife. Specifics vary, but the products are toxic to fish and other wildlife. To reduce the chance of environmental contamination, proper protective measures must be an integral part of all your wood preservation operations.

Groundwater Pollution

Use of wood preservatives has been cited as a source of pollution in surface and groundwater in many parts of this country. Testing has documented contamination in public and private wells at levels exceeding health advisories. In some cases, sources of contamination are obvious—for example, spills or illegal discharge of chemicals into ditches, storm drains, or sewers. However, groundwater typically is affected by contamination of the overlying soil. Such contamination usually is the result of applying preservatives to soil, spills, overflow from tanks or holding ponds, and improper disposal. Another less obvious source is the uncontained drippings from freshly treated wood. In many communities, groundwater is the only source of drinking water. When groundwater becomes contaminated with any chemical, cleanup, where possible, is very difficult and costly.

Waste Disposal

Some treating plants discharge wastes into approved municipal sewer systems for processing with municipal wastes. Many plants use closed chemical and wastewater recovery systems to contain wastes that could be harmful. Recovered solutions can be reused. If they are contaminated, they can be filtered to remove solid wastes. Liquid waste materials can be diverted to settling tanks or lined ponds.

Use door sumps under pressure-chamber doors and hard-surfaced drainage areas. Any excess chemicals that drip or are rinsed from freshly treated material thus are channeled into the waste or recovery system. It also is important to contain runoff from areas where toxic chemicals are used in order to protect stored logs, poles, or lumber before processing or during seasoning.

Treating vessels and drip pads must be covered to reduce the risk of rainwater runoff, and plants must routinely monitor storm water runoff to ensure that contaminated water does not leave the site.

Storage and Disposal of Containers

Store chemicals in a dry, well-ventilated, locked area. Keep them in well-sealed containers whenever possible. Protect liquid storage against tank rupture. Protect concrete vats against freezing, cracking, or spillage. Wherever spills, leaks, or flooding could occur, be sure that runoff will drain into a recovery or disposal system.

Thoroughly rinse containers and empty them into storage or treating tanks before disposal.

Dispose of containers at an approved landfill or by other approved means.

Be particularly careful not to contaminate streams or groundwater.

Be sure to read and follow the label requirements and the Product Safety Data Sheet (PSDS) for each preservative. If you are not sure how to store a product safely or dispose of the empty containers, contact the chemical supplier or your state agency that regulates storage and container disposal.


Cleanup procedures depend on the chemical involved. Treating-plant personnel should know what chemicals are being stored and used, and they should have a plan for handling spills. All workers who might be involved should know what help is available and whom to notify in case of a major spill.

Limitations on Use

Recent EPA regulations on wood preservatives include some limitations on treating wood intended for certain uses. Be sure that the label allows you to use the preservatives for the specific use you intend. Not all of these limitations are the responsibility of commercial applicators but these limitations should be known.

Product Safety Data Sheets (PSDS) are available from wood preservative manufacturers and distributors. These sheets contain information on such topics as toxicity and first aid, personal protection and controls, storage and handling precautions, spill-leak disposal practices, transportation, physical data and reactivity data. You should have a PSDS on file for each different formulation that you use.

Voluntary Consumer Awareness Program

In order to inform consumers of the proper uses of treated wood and the proper precautionary measures to take when using such wood, the treated wood industry has developed a voluntary Consumer Awareness Program (CAP). The treated wood industry is committed to the implementation of the CAP and the education of the consuming public.



Practice Questions


1) Wood preservative chemicals selectively control only wood destroying organisms.

  1. True
  2. False

2) Groundwater typically is affected by contamination of the overlying soil.

  1. True
  2. False

3) Which of the following is often overlooked as a source of pollution of surface and groundwater in many parts of the country?

  1. Uncontained drippings from freshly treated wood
  2. Overflow from tanks or holding ponds
  3. Improper disposal of wood preservative chemicals
  4. Accidental spills

4) Detailed information on acute and chronic toxicity, storage and handling precautions, and physical and reactivity data for wood preservatives is available from ____________.

  1. product labels
  2. product safety data sheets
  3. distributor brochures
  4. advertisements


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University of Kentucky College of Agriculture | S-225 Agricultural Science Center North, Lexington, KY 40546-0091 | 859.257.7450
An Equal Opportunity University | Last modified 11/30/2018