State authorities are warning Oregon cannabis growers to be careful using pesticides.

The Oregon Department of Agriculture said Wednesday it has drawn up a pesticide advisory, which the Oregon Health Authority is sending to registered medical cannabis growers around the state.

The advisory says no pesticides have been specifically approved for use on cannabis, which is still illegal on a federal level, and the health and safety impacts on cannabis workers have not been evaluated.

Department of Agriculture spokesman Bruce Pokarney says regulations for pesticide use are being drawn up along with a host of other rules for growing and selling retail cannabis.

Full retail cannabis sales are not to begin until late in 2016, but in October medical cannabis dispensaries can start selling limited amounts to anyone over 21.