Obviously, the first and best option is to reuse any extra panels or the off-cuts created because that keeps material out of landfill sites. That’s also a great way to reduce costs – why pay to purchase the material and pay again to haul it away to a landfill? Just find another project to use it on.
Another option is to convert it to mulch. Tests done at the University of Georgia showed that mulch created from OSB and other job-site lumber had little or no impact on the environment, including the soil below it.
From the green building perspective most, if not all, green building standards give points or credit for using OSB on a project.
To address the question directly I am not aware of any studies that indicate any harm from OSB being disposed of in a landfill site but again; to reuse or repurpose it is absolutely the best practice.