A couple of years ago I watched a show on PBS called “Growing a Greener World”. In one episode the host of the show discussed what happened to his raised garden beds. He had bought compost from somewhere in which some of the raw materials contained herbicides...and nothing grew in that compost.

I would avoid it so you don't take the chance. Assuming you are just needing it as the brown bulk of the compost.... since we are getting into the fall... look for stockpiling leaves (your own, your neighbors, etc) .... you can many times ask tree trimming services to dump some wood chips on your property if they are in the area..... or you can just purchase the basic wood mulch if needed.

I need some browns ASAP as I have fruit flies in the bin and too Much greens.

we live in a new construction area so there are no leaves around. I went to the local park for some bags but it wasn’t enough (though I got a lot of strange looks even though I asked permission from the authorities)

Fruit flies are harmless and don’t affect either the compost or the garden. There’s no need to worry about them. Do you have any cardboard or paper? Cutdown perennial stems?

They aren’t harmful but somehow are finding their way into the house (bin is close by) and it’s making me nuts.

so I need to at least limit them.

I do have cardboard and paper can I use Cut down annuals ?

Lots of shredded paper, cardboard, leaves, wood chips, wood shavings, sawdust. But you'll have to add a lot continuously to keep fruit flies controlled. You can keep them down somewhat but they'll come back. You may want to consider relocating your bin further away. In my case they stay pretty close to the bin - mostly inside the bin - so it doesn't really need to be that far, but you'll have to figure out what you can tolerate.

I don't understand all this....for years and years i have maintained a compost pile. Actually 2 piles, this years and the one from last year that is now ready for use. I put everything into it, evergreen clippings, annual stems and spent flowers, weeds ( but for creeping charlie!) raked leaves, fallen apples, rotting pumpkins and gourds, potato peelings etc. Occasionally I would add a fork full of finished compost to the this year's pile and turn it, but pretty much I did nothing. BUT no grass clippings that had herbicide or grub killer within 2 months.
What did the grower of that hay intend it for? Cattle feed? Bedding?...and they didn't know if there was herbicide residue? EWW!

The well known problem with herbicide is to do with clopyralid, picloram and aminopyralid which are used commercially for weed control. These herbicides can persist even in the manure from animals which have grazed on treated grass. They don’t bother the animals but can destroy gardens where the manure (or hay) is used. They persist far longer than two months.

Here's my take on the story at floral uk's link above:

"In 2009/10 reports of weedkiller damage across many allotments and some gardens in the UK were traced back to farmyard and stable manures as the source of the contamination."

What's important to me is the date

"The complexity of the supply chain means it is not always easy to trace the source of the contamination. You try by contacting the supplier of your manure in the first instance to discover which weedkillers were used and who the manufacturers are."

To me this implies the suppliers are of bagged manure.

"Unfortunately, residues in manure can remain for extended periods, even up to two years. The best advice is to return the unused manure to the supplier" .....

More evidence of bagged manure.

"Products containing aminopyralid were temporarily withdrawn from supply, sale and use. Following investigation, new approvals have now been given by the HSE."

So IS there really a problem?

I find a barn and ask the owner for permission to haul off some of their unwanted stock of manure. Personally I am not going to look them in the eye and question the quality of his free manure, and I certainly am NOT going to return the manure to their pile.

It's my opinion that horse owners have a big investment in their facility and in their horses and are not going to take any unnecessary risks. I have been using or have helped family members haul manure since the 1950's and have never heard of a problem.

The precautions discussed should include a caution to check the source of the manure in a bagged product. Personally I wouldn't eat food from some sources and also wouldn't buy manure that comes from those same sources.

I think that compost is a very helpful gardening product and I think that if you want to enlarge or open a new garden that you will be very unlikely to have the compost available on site to make that possible. Manure is the go to replacement and it bothers me there's so much unwarranted bashing of this resource in the gardening community.