The messy merger highlights the fallout from the steep drop in the price of oil and natural gas. Consumers are benefiting from inexpensive gasoline, but the record-low prices are causing severe pain radiating from the Texas Panhandle to Wall Street.

The low prices combined with high levels of debt could push 175 global exploration and production companies – more than a third of the industry – into bankruptcy, according to a report by the consulting firm Deloitte. Oil giants like Royal Dutch Shell and Chevron have laid off workers as profits have plunged. On Wall Street, banks that made big loans to energy companies are bracing for big losses. This week, JPMorgan Chase increased its reserves for bad energy loans.

As the troubles in the energy industry broaden, the risks around Energy Transfer’s Williams acquisition have increased and the company’s financial picture continues to dim. In February, Energy Transfer replaced its chief financial officer, Jamie Welch, a former investment banker at Credit Suisse who helped structure the deal. On a conference call on Thursday, an analyst asked why Mr. Welch had left, and Mr. Warren said, “The decision was made by me that we needed to make a move and we did,” without elaborating further.

Another looming problem: Under the terms of the deal, Energy Transfer has to pay $6 billion in cash to Williams as part of the cash-and-stock acquisition. To do that, it has to either raise additional debt or sell assets. With energy prices still slumping, neither option is particularly attractive. On top of that, there is also a risk that one of Williams’s biggest customers, Chesapeake Energy, could file for bankruptcy.

Short of filing for bankruptcy itself, Energy Transfer is stuck buying Williams because of stringent deal terms, according to several people involved in the transaction. Williams shareholders, however, could still vote down the merger.

“From the minute they announced the deal, everything that they needed to go right for this deal to work hasn’t. It’s all gone the other way,” said Keith C. Goddard, chief executive of the investment management firm Capital Advisors of Tulsa, Okla., which owns 220,000 shares of Williams. Mr. Goddard said he would vote no on the merger. “At what point do these directors say, ‘We’re not doing this deal’?”