Planting your own fruits and vegetables has become a growing trend. But what you may not know is that the garden box you're working in could be contaminating your food.

Vern Nelson knows. As the garden columnist for the Oregonian, he is an expert on everything garden. Like many gardeners, he used to use CCA pressure treated wood to build his garden boxes. That is until he learned they leached.

“What I discovered was that the CCA wood leaches. The stuff comes out and ends up in the soil,” explained Nelson. CCA stands for chromated copper arsenate.

Up until 2004 most garden boxes were made from CCA treated wood. The chemicals helped prolong the life of the wood. But studies now show that when wet the wood leaches arsenic into the surrounding soil and anything planted nearby. Studies have shown that food planted in these beds will absorb some amount of arsenic

Sara Leverette, program director for Oregon Environmental Council, studies the dangers of CCA treated wood. “Arsenic is a widely acknowledged carcinogen,” explained Leverette.

Leverette acknowledges, the levels found in any fruits and vegetables would likely not be high enough to pose a serious health risk but adds prolonged exposure to arsenic has been shown to cause cancer.

In January 2004, the Environmental Protection Agency banned the sale of CCA treated wood. But if you built your garden box before that, there’s a good chance it was treated with chemical.

Paul Hastings, manager of Portland Nursery recommends gardeners use wood treated with linseed oil or recycled plastic garden boxes.

As for Vern, his vegetable garden is now arsenic-free. He replaced all the treated-wood with the natural kind. Noted Vern, “Keep your garden healthy and it will help keep you healthy.”

The Oregon Environmental Council also warns against using recycled pressure treated wood. If it's older wood, it may have been treated with arsenic.