A growing group of lawmakers want to question government contractors involved in the costly and troubled rollout of the new health care law.

An inquiry into the troubled Obamacare program Thursday by the House Energy and Commerce Committee is likely to be just the first of many probing what went wrong. The new health care law requires everyone to buy insurance, but when Americans tried to enroll in the health insurance exchanges online, they were frustrated by long delays and other glitches.

Also on Thursday, House Government Reform and Oversight Committee aides said they had already learned from several key contractors that the White House did not "heed warnings" that the website was not ready and needed additional testing before its Oct. 1 launch date.

The oversight panel is now demanding answers — by close of business Friday — from 11 companies hired by the Obama administration to design and implement the health care roll out, including Booz Allen Hamilton, the Mitre Corporation and CGI Federal.

Who got what

According to House investigators, up to 55 contractors received between $400 and 600 million to develop the federal exchange and website. The last firm listed was paid to process paper applications for health insurance.

Serco, Inc.: $1.2 billion
CGI Group Inc.: $88 million
Quality Software Services Inc.: $55 million
Booz Allen Hamilton: $37 million
National Government Services Inc.: $31 million
The Mitre Corp.: $22 million
Logistics Management Institute: $19 million
Genova Technology: $16 million
Terremark Federal Group: $15.5 million
IDL Solutions, Inc.: $9 million
Navigant Consulting: $8.9 million

Source: House Committee on Oversight and Government Reform

The Senate Finance and Judiciary committees also are looking for answers from the vendors. Top Republicans on the committees, Orrin Hatch of Utah and Chuck Grassley of Iowa, wrote Thursday to 47 companies paid by the federal government to help launch the online sign up for the health car law.

Among other things, Hatch and Grassley asked the companies to provide lists of all contract modifications and the timetables for when those changes were ordered.

Booz Allen, according to the House panel, was paid at least $37 million by the Center for Medicare and Medicaid Services to help develop the Healthcare.gov website, while CGI received $88 million and Mitre was awarded $22 million for their work on site.

Oversight Committee Chairman Darrell Issa, R-Calif., said preliminary interviews with contractors indicate the Obama administration called on the companies to "abandon the anonymous shopper feature" and demanded other changes too close to the launch date for the firms to comply with the requests and adequately test how the changes affected the site.

The anonymous shopper feature would have allowed interested enrollees to browse insurance plan rates anonymously, without having to go through the time-consuming process of providing detailed personal information.

According to the letter, the companies were forced to pivot just before the launch so that every shopper of health insurance would have to first provide that detailed information.

This last-minute change, Issa said, likely contributed to the widespread website malfunction.

Issa notes in the letter that the website received "little, if any testing," which could jeopardize the privacy of those who logged on to the site and provided the required personal information.

Issa said the federal government paid up to $600 million for 55 outside contractors to work on the troubled program.

President Obama earlier this week said he too was frustrated by the site's problems and pledged to institute a "tech surge" to repair it.