Bagged garden soils have no information about their source or safety. I recently bought bags (big box store) and am concerned about where the soil was actually mined. There were some weird things included in each of the three bags that were definitely not related to natural soils. I read the bag labels, other than the state (MI) or country (MX) there was no specific information about where the soil came from. Fearing the worst I am turning to you. Where can I find information about oversight and safety of soils entering Oregon?
I believe you are correct to be suspicious of your bagged soil mix. Often they contain a combination of mined peat from Canada, mineral soil from building or mine sites, various agricultural wastes (rice hulls, shredded coconut husks, bark mulch). Unfortunately, bagged or potting soil mixes are not regulated to my knowledge. The Oregon Department of Agriculture only regulates products containing fertilizer. Importation of foreign soils to the US is regulated and phytosanitary certificates paper work are required, but the bagged soil you purchase at a big box store doesn't require this. The soils SHOULD be tested for concentrations of heavy metals. Directly contacting the manufacturer is your best bet. You can also look for products labeled with an OMRI certification (Organic Materials Review Institute), ensures product must comply with USDA organic rules. The Mulch and Soil Council also provides a certification - and seem to have a good program, so look out for their certification.
Additional ODA information if you interested. You may try contacting someone here if you are highly concerned.