In a new report, the Government Accountability Office estimated that if the cost-containment measures put in place by President Obama’s health care law prove unsustainable, then the law will add substantially to the nation’s long-term debt.

The report, requested by the ranking Republican member of the Senate Budget Committee, Jeff Sessions, estimates that over a 75-year period, the health care law could add debt equal to 0.7 percent of the nation’s economic output. Though the report itself doesn’t contain a dollar figure, Sessions’ office said the GAO confirmed to his staff that this would translate into $6.2 trillion.

Speaking about the report at a hearing this morning, Sessions said the report contradicted Obama’s pledge that health care legislation wouldn’t add a dime to deficits.

Proponents of the law would note that the GAO report says that if all of the proposed savings and tax increases remain in place, Obamacare would still be deficit reducing overall. But the health care law contains a number of cost containment experiments that some have argued may not produce the projected cost savings. In addition, it makes cuts to Medicare providers that skeptics, including the former chief actuary of the program, have argued could force some health providers to stop accepting Medicare patients, thus reducing access. This could put pressure on lawmakers to undo the proposed cuts, thereby increasing the cost of the health care law.

Read the full GAO report here.