Understanding Compost Contamination

Although compost is overwhelmingly safe and beneficial for the environment, it is useful to know about potential contamination sources in order to make good choices when buying and using compost. Read on below to better understand potential contaminants including persistent herbicides and man made inerts.

Persistent Herbicides

The compost industry still contends with the lasting effect of a some chemical broadleaf weed killers that can survive the composting process and negatively affect plants grown in such compost. These Persistent Herbicides have active chemical ingredients that can persist on treated vegetation for years, even after composting.

The USCC recognizes the threat these chemicals pose to our compost manufacturers and the end users of compost products that could contain them. Use the resources below to fight this threat.

The USCC also has a permanent standing subcommittee – the Legislative and Environmental Affairs Committee – to focus on and fight persistent herbicides. Click on the link to learn more about their work.

Man-Made Inerts (Trash)

Man-made inerts refer to the trash that get mixed into the compost feedstocks (ingredients) and end up in compost. They can include plastic, textiles, glass and other objects that don’t decompose entirely during the compost manufacturing process. It is difficult to sift these out of compost after they arrive at the facility. Please help us keep these items out of compost by being mindful of what you put into your yard waste bin.  While man-made inerts not generally dangerous, they do decrease the quality of compost and can be aesthetically offensive.

Man-made inerts is one of the characteristics measured during the STA-certification process. To read more about inerts and the other characteristics that are measured for during the STA-certification process, click on the link below.

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