* Unaware of environmental impact from Oklahoma accident - CEO
* Still assessing financial impact from incident
* 4th-qtr adjusted loss 10 cents/shr vs est 8 cents
* Shares fall 9 percent amid broader market decline (Adds CEO quote on Oklahoma accident, updates stock price)
By Ahmed Farhatha
Feb 8 (Reuters) - Patterson-UTI Energy Inc, which is dealing with the fallout of a drilling accident that killed five workers last month, reported a bigger-than-expected quarterly loss on Thursday as expenses more than doubled.
Shares of the Houston-based oil and gas driller fell 9 percent to $19.98 on the New York Stock Exchange amid a broader market selloff.
The accident at an oil well in Oklahoma last month — the deadliest U.S. drilling accident since the Deepwater Horizon rig explosion in 2010 — has sparked debates about worker safety in the shale industry and its impact on the environment.
The cause for the accident is still being investigated.
In a call with analysts, Patterson Chief Executive Andy Hendricks said his company was still assessing the financial impact from the accident.
"While we carry pollution insurance coverage, we are not aware at this time of any meaningful environmental impact from the accident," he said.
For the fourth quarter ended Dec. 31, Patterson earned $8,010 per day on average from its 161 active rigs. Analysts at Jefferies had estimated earnings of $7,279.
The company reported a net profit of $195.4 million, compared to a loss of $78.1 million a year earlier, benefiting from a nearly $227 million gain from new U.S. tax laws.
Excluding one-time items, Patterson reported a loss of 10 cents per share, bigger than analysts' average estimate of an 8-cent loss, according to Thomson Reuters I/B/E/S.
Expenses jumped to $809 million from $360.1 million.
Revenue climbed to $787.3 million from $246.9 million a year ago, helped by higher drilling activity. Analysts had expected revenue of $764.5 million. (Reporting by Ahmed Farhatha in Bengaluru; Editing by Saumyadeb Chakrabarty and Sai Sachin Ravikumar)