UPDATE 1-Distributors' 'mountain' of pills fueled opioid epidemic, W.Va. judge told

(Adds start of argument, quote from plaintiffs’ lawyer)

May 3 (Reuters) - A city and county in West Virginia launched their case against the three largest U.S. drug distributors at a widely anticipated trial on Monday, accusing them of fueling the opioid crisis that has resulted in nearly 500,000 overdose deaths in the United States over two decades.

“We intend to prove the simple truth that the distributor defendants sold a mountain of opioid pills into our community, fueling the opioid epidemic,” Paul Farrell, a lawyer for the city of Huntington and Cabell County, said in his opening statement in Charleston, West Virginia.

Lawyers for the distributors - AmerisourceBergen Corp , McKesson Corp and Cardinal Health Inc - are expected to give their opening statements later in the day.

The companies have denied the claims, arguing they cannot be liable for distributing pills that were prescribed by doctors.

Huntington and Cabell, along with other West Virginia towns and counties, opted out of a proposed $26 billion nationwide settlement with the three distributors and drugmaker Johnson & Johnson.

A verdict in the trial, before U.S. District Judge David Faber, could help lay the groundwork for settlements in the sprawling nationwide litigation over the opioid crisis, which encompasses more than 3,300 lawsuits by local governments around the country against opioid manufacturers, distributors and pharmacies.

Opioids resulted in the overdose deaths of nearly 500,000 people in the United States from 1999 to 2019, according to the U.S. Centers for Disease Control and Prevention. West Virginia is among the hardest hit states, recording more opioid prescriptions and overdose deaths per capita than any other in 2018, according to data from the National Institutes of Health.

Another opioid trial is underway in a case brought by California counties against J&J and other drugmakers, and a trial in a case brought by New York counties is scheduled to begin next month. (Reporting By Brendan Pierson in New York; Editing by Noeleen Walder, Bill Berkrot and Steve Orlofsky)