The Paleocene Eocene Thermal Maximum (PETM) is a warming event that occurred ~56 million years ago. Likely caused by a large release of carbon dioxide into the atmosphere, it led to ocean acidification and big changes in ecosystems. Because it is similar to today's changing climate, it is used as a future analog. A key question is how ocean oxygen levels responded globally. Research gives different answers due to local records that don't always align. In this study, we investigate a new site (U1557) using local and global proxies. Then, we use thallium isotopes to gain a global perspective of PETM ocean oxygen changes by analyzing U1557 with a well-studied site (1263). Thallium isotopes reflect large-scale changes because they reflect how manganese oxides are buried - a process sensitive to global oxygen levels. The local results from U1557 show lower oxygen during the peak of the PETM, which differs from the global results of U1557 and 1263 that show higher oxygen during the peak. The difference between results indicates that thallium isotopes should reflect global signals that are independent of local changes. This helps separate local signals from global and better predict how ocean oxygen may change in the future.