BOSTON, May 21 (Reuters) - Canada's Irving Oil rejected former top executive Mike Ashar's allegation that he was underpaid millions of dollars, painting him instead as an "unsuccessful" hire who oversaw a decline in the family-owned company's worth during his five-year tenure, according to court documents filed this week.
The legal battle has offered a rare glimpse inside the closely-held company, which runs Canada's largest oil refinery in the Atlantic province of New Brunswick, and is planning to build a storage terminal for the country's most ambitious oil pipeline project, TransCanada's Energy East.
Ashar, who became the first non-member of the billionaire Irving family to run Irving Oil when he was hired in 2008, filed a lawsuit in March, saying the family had created a "poisoned work environment", spied on his emails after his departure, and denied him an agreed bonus of about $50 million.
He said the decision to withhold the bonus was based on a flawed study of the company's value over the course of his tenure that did not take into account his contributions - including his role in the Energy East project, and his establishment of oil deliveries to the refinery by rail.
Irving filed a response on Tuesday asking the Saint John Court of Queen's Bench to dismiss Ashar's claim.
"Ashar's tenure ... proved to be unsuccessful. The equity value of Irving Company and Irving Limited decreased under Ashar's leadership," according to the filing.
Irving said it had become "increasingly dissatisfied" with Ashar over the years, and that Ashar had expressed a desire to leave because his family did not like living in Saint John, the industrial city where Irving is headquartered.
Irving added that Ashar was paid some $20 million upon his departure in 2013, representing "the entirety of Irving Limited's remaining obligations." The company admitted in the filings that it monitored Ashar's email for several months after his successor was chosen, but that it was entitled to do so.
"Among other things, this allowed Irving Limited to identify and address email correspondence related to the business of Irving Limited," it said.
Ashar was executive vice-president at Alberta-based oil sands producer Suncor before he joined Irving. He is now CEO of energy company Cairn India. Ashar did not respond to a request for comment.
Ashar's successor, Paul Browning, left Irving Oil in August 2014, less than two years after he was hired. The company has not chosen a replacement. (Editing by Paul Simao)