Cremation on site is the preferred method. If that’s not possible burial at least 6 feet deep after prepping the bodies. They typically cover the bodies with agricultural lye and then sanitize the surrounding soil after burial.

If the proper procedures are done, this really shouldn’t be an issue. Anthrax that hasn’t been exposed to air isn’t that much of a contamination issue as it doesn’t develop the protective spore unless exposed to oxygen.

I’d be willing to guess that this sight was probably chosen for cremation. Most of the time if they are unable to do a cremation on site it’s because the area isn’t fire safe.