WASHINGTON -- Energy Secretary Steven Chu went face to face with Republican lawmakers Thursday and vigorously defended his department against charges of poor judgment and political favoritism in granting $535 million in loan guarantees to the now-bankrupt solar-panel maker Solyndra.

In a five-hour hearing of a House subcommittee, Republican lawmakers zeroed in on two issues. They accused Chu of breaking the law in October 2010 when his department agreed to let new investors in the cash-starved company get first place in line for repayment, ahead of taxpayers, if Solyndra ever went bankrupt. And they grilled Chu about whether he ignored warnings that the price of solar panels would plunge, threatening Solyndra's viability.

Chu responded that Solyndra was the victim of a " very bad tsunami" that hit all solar manufacturers by pushing panel prices down 40 percent in one year. And he repeatedly asserted that the financial terms for investors, who added $75 million to Solyndra, were approved only after he got the green light from his own general counsel as well as from an outside law firm, Morrison & Foerster.

"We believe there was no violation of the law," Chu said.

"That seems like a tortured legal reading of a fairly straightforward law," replied Rep. Michael Burgess, R-Texas.

Democrats rallied to Chu's defense, saying that the harsh questioning reflected House Republicans' aversion to supporting clean-energy technologies that might antagonize the oil and coal industries.

Henry Waxman, Calif., the ranking Democrat on the House Energy and Commerce Committee, called the long-running investigation of the Solyndra loan "a distraction" and said it was "time for House Republicans to stop dancing on Solyndra's grave and start getting serious about energy policy."