Answer: There was a time when pressure treated lumber contained arsenic (CCA) and was not considered safe for use in raised vegetable gardens because the arsenic leached out into the soil. The newest method for treating wood is Micronized Copper Quaternary (MCQ). It is chemically different than the old CCA treatments. It is made of tiny (micro) particles of copper. These particles are forced into the wood cells or pores during the pressure cycle. Once in, they stay in, also forming a barrier keeping in the quaternary. The leaching of chemicals out of MCQ is practically non-existent and using the treated lumber for a vegetable bed is safe because the chemicals do not leach out into the soil. You can use the wood in your raised garden.
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