All chemical products must be approved by regulatory bodies. In the U.S. the Enviromental Protection Agency approved the use of CCA through a verification process between 1978 and 1986 and is currently conducting a reregistration. In Canada Heath Canada is conducting similar reviews as ongoing verification as well. Additional scientific research has been undertaken to evaluate human health risk of CCA treated wood.

Renowned toxicologist Dr. Barbara Beck of Gradients Corporation completed a human health risk assessment in October of 2001. Dr. Beck's team studied the potential for dermal contact with and ingestion of arsenic dislodged from CCA-preserved wood structures as well as ingestion, dermal contact, and inhalation of soil containing arsenic released from CCA-treated wood structures. The study included a summary of the estimated cancer and non-cancer health risks from subchronic {age 2-6} and chronic {ages 2-31} exposures to arsenic in soil, and dislodgeable arsenic on two different types of treated wood. The treated wood types included the commonly used Southern Pine, and the wood type associated with the highest risk-Southern Pine w/ Pressure-applied Water Repellent. The study concluded that both the cancer and non-cancer health risks from exposure to arsenic in CCA-preserved wood fall within the EPA's acceptable risk limits.

Florida State University toxicology program director Dr. Christopher Teaf conducted three studies in 2000 and 2001 to determine safe levels of exposure to arsenic from CCA-preserved wood in decks, playgrounds and the soil beneath them. Wood Surface Exposure. Tests by the consumer Product Safety Commission and others show that CCA-treated wood for playground use generally had surface levels of arsenic below 6.3 micrograms per 100 square centimeters. Taking hand-to-mouth contact into consideration, Dr. Teaf found that an average level of 420 micrograms per 100 square centimeters of wood surface is safe for occasional childhood exposure {5 years} and 40 micrograms per 100 square centimeters for long-term exposure {30 years}. Dr, Teaf found that the levels of arsenic generally reported were well within the zone of safety.

Dr. Teaf found that acceptable average levels of arsenic in soil under CCA-treated decks ranged from 170 parts per million for long-term exposure {30 years} to 390 parts per million for occasional childhood exposure {5 years}. He also found that acceptable average levels of arsenic in soil under CCA-treated playground equipment ranged from 90 parts per million for long-term exposure{30 years} to 260 parts per million for occasional childhood exposure {5 years}. These acceptable levels for arsenic in soil under decks and playground equipment are far higher than what academic researchers and the media generally report finding in the soil under decks and playground equipement.

A Consumer Product Safety Commission study by the Health Sciences staff measured dislodgeable arsenic in eight samples of CCA-preserved wood. Five of the samples had an undetectable amount of arsenic; two other samples yielded small quantities. The highest yield in the eighth sample was not found in rough-sawn lumber, a type of lumber classified as not acceptable for playground equipment by the wood-treatment industry. This led John Preston of the CPSC Division of Mechanical Engineering to conclude, "…the amount were much below the level that makes a difference to health. I have no problems with telling consumers that it's appropriate for playground use." The CPSC announced in August 2001 that it will conduct a new risk assessment. The assessment will include data collection from 75 playgrounds, 25 in each of three geographic areas, and the analysis of that data is scheduled for release in summer of 2002.

Epidemiology studies: Three separate studies conducted on the health status of wood-treatment plant workers and carpenters found that they have shown no increased risk of cancer or other health problems due to that high level of exposure.

Evaluation of Risk to Children Using Arsenic-treated Playground Equipment:
This study for the California State Department of Health Studies found that there is negligible risk to children from exposure to CCA-preserved materials.

Evaluation the Environmental Risks Associated With the use of Chronomated
Copper Arsenate-Treated Wood Products in Aquatic Environments: Dr.Kenneth M. Brooks conducted this study of the effects of CCA-preserved wood on the aquatic environment in Washington State. His study found that CCA-preserved wood being properly used in aquatic environments is effective and safe.

Arsenic Availability from CCA Treated Lumber and Uptake by plants: University of Minnesota researchers found that vegetables in gardens using CCA-treated wood accumulated some arsenic from the wood, but the amounts accumulated were well within U.S. Public Health Service standards.