NEW YORK: Emails sent under a pseudonym by current US Secretary of State Rex Tillerson when he was still CEO of ExxonMobil, and which are sought by a court, cannot be produced, lawyers for the oil giant said. According to a letter dated March 21 and sent Wednesday by ExxonMobil to AFP, these emails, sent under the name Wayne Tracker, cannot be recovered for the period from September 5, 2014 to November 28, 2014. The letter is addressed to the Supreme Court of the State of New York as part of an investigation opened in November 2015 by State Attorney General Eric Schneiderman. It is investigating whether ExxonMobil had adequately informed investors and the general public of potential financial risks posed by the need to limit the use of fossil fuels to fight global warming. The probe established that Tillerson had used a personal account under the pseudonym Wayne Tracker for a number of years, in addition to his official corporate email account. Wayne is his middle name. As the Wayne Tracker account was classified as non-personal, it was “exempted from the suspension of the ordinary course ‘file sweep,'” the letter said. Attorneys for ExxonMobil said that after several search series on this account, it was not possible to produce emails between September 5, 2014 and November 28, 2014. The issue was limited to the Wayne Tracker account, according to the letter. Schneiderman said in mid-March that Tillerson used this email address between 2008 and 2015 to communicate with other group leaders on a number of issues including those linked to climate change. A spokesman for ExxonMobil told AFP on Wednesday that “many of the emails from the secondary account (Wayne Tracker) were also available from Tillerson’s primary account or from email accounts of employees he communicated with, which were on litigation hold.” He added that at a Wednesday hearing the New York State Supreme Court found that the oil group had responded adequately to Schneiderman’s demands. Tillerson, who celebrates his 65th birthday on Thursday, took the helm of ExxonMobil in 2006 and adopted sharply contrasting views with those of his predecessor Lee Raymond on global warming. He notably spoke up in favor of a carbon tax in 2009. But as head of the State Department Tillerson now works under the administration of President Donald Trump, which has voiced skepticism of climate-change science.