(CNN) - On the final weekend before Super Tuesday, Sen. Barack Obama's presidential campaign quickly responded to a New York Times article Sunday scrutinizing the senator's actions on a nuclear leak bill. The story, published on the front page, said "a close look at the path his legislation took tells a different story" from what Obama has said.
Obama's campaign posted on its Web site a lengthy "fact check" about the article defending the senator's work on the bill.
Two years ago, after Illinois residents learned that Exelon Corporation did not disclose leaks at one of its plants, Obama introduced the Nuclear Release Notice Act of 2006, which would require plant owners to report all leaks to state and local authorities, the article reported.
Obama has touted the bill - which never passed the Senate - on the campaign trail, and in December he told voters in Iowa it was "the only nuclear legislation that I've passed," the newspaper reported.
Although it passed the environmental committee, the bill never made to the full Senate, and the senator reintroduced it last fall, according to the report.
The article said the Obama camp did not explain to the newspaper why Obama told Iowa voters that the bill had passed.
The article also said Obama bowed to pressure from Senate Republicans, Exelon and nuclear regulators, and rewrote the bill to "reflect changes" they wanted.
"The new bill removed language mandating prompt reporting and simply offered guidance to regulators," the story said.
In its "fact check," the Obama campaign said the revised bill still required notification of leaks and that "the only change was that the requirements would be made through the regulatory process."
The "fact check" also said Obama had "criticized the industry's voluntary guidelines and vowed to press ahead with the bill after those guidelines were announced."
The "fact check" did not address Obama's remark about the bill having "passed." It also did not respond to the article's reporting that Exelon executives and employees have contributed $227,000 to Obama's campaign.
David Axelrod, Obama's chief political strategist, has worked as a consultant for the Illinois-based company, the newspaper reported.
"Obama 'never discussed this issue or this bill' with Mr. Axelrod," the article said, citing Obama's campaign.
Obama is locked in a tight race for the Democratic nomination against Sen. Hillary Clinton of New York.