Updated at 2:35 p.m. ET on Friday 5/31
(CNN) – In the early days of President Barack Obama's sweeping new health care law, Douglas Shulman, then the commissioner of the Internal Revenue Service, was cleared to visit the White House 157 times over three years, official visitor logs show.
More than 50 of Douglas Shulman's scheduled visits are described as "health care meetings" or "health care reform meetings," according to the visitor logs. Arrival times are only listed for 11 of his visits, and it's not unusual for a person to appear on the visitor logs - which are derived from Secret Service clearance lists - without actually having visited the White House. The majority of the visits were set to be held in the Eisenhower Executive Office Building, which houses office suites for administration aides.
The IRS, which has come under fire for its admitted targeting of conservative groups applying to become tax exempt, is responsible for enforcing many of the new rules associated with Obamacare, which was signed into law on March 23, 2010.
Official White House visitor logs show Shulman's scheduled White House visits came between October 2009 and December 2012. Shulman was appointed by President Bush in 2008 and left the post in November 2012. On Fox News Thursday, Shulman's predecessor Mark Everson stated he'd only visited the White House once during his tenure as IRS commissioner, though visitor logs for the Bush administration aren't available publically online.
According to an inspector general report from earlier this May, March 2010 was the month IRS agents began filtering applications for tax-exempt status using the words "tea party" and "patriot." The agency experienced a flood of new applications after the Supreme Court decision in the Citizens United case that opened the door to increased corporate and private political spending.
Of Shulman's meetings recorded in the visitor logs, 40 listed his "visitee" as Nancy Ann DeParle, who acted as the director of the White House Office of Health Reform until 2011, when she moved into the role of deputy chief of staff for policy. Fifty-four visit records list Sarah Fenn as Shulman's "visitee." Fenn is listed as a staff assistant in 2010 White House salary records. In 2011 she's described as "assistant counsel of ethics."
Five visits listed Obama as the "visitee."
The president's health care law created a massive new workload for the IRS, which is charged with issuing and enforcing rules related to Obamacare. The agency's tasks include collecting information for employers and insurers; figuring out who qualified for subsidies or Medicaid, determining who must pay a penalty for not obtaining insurance, and penalizing employers that don't provide affordable coverage to their employees.
"Tax provisions included in the Affordable Care Act represent the largest set of tax law changes the IRS has had to implement in more than 20 years," the Treasury Inspector General for Tax Administration noted in a recent report.
The ACA has some 500 provisions, and more than 40 amend or add provisions to the tax code, according to the report.
In congressional testimony earlier this month, Shulman was quizzed on his visits to the White House. He attributed one visit to taking his children to the annual Easter egg roll hosted by the president and first lady, but said at no point did he talk to anyone at the White House about the agency's tax exempt rules. White House Press Secretary Jay Carney backed up that claim last week, saying "An IRS commissioner appropriately has - or his designees have - meetings on matters of policy all the time, but not discussions about enforcement or applications for tax exempt status."
Speaking in separate testimony before the Senate Finance Committee, Shulman said that he was aware of some aspects of his agency's targeting of conservative groups in the spring of 2012, and took what he called the correct action of ensuring the situation would be independently reviewed.
But he denied full awareness of what was happening at the time, saying subordinates failed to inform him of the details.
Top White House officials say they knew nothing of the targeting when it occurred. General Counsel Kathryn Ruemmler learned of the pending inspector general's report on April 24, 2013, according to Carney. She later informed other top Obama aides, including chief of staff Denis McDonough.
Carney insisted no one - including Ruemmler and McDonough - told Obama anything about the inspector general's pending report before media reports about it began appearing on May 10.
CNN's Kevin Liptak and CNNMoney's Jeanne Sahadi contributed to this report.