JACKSON, Miss. (AP) — A former director of biofuel maker KiOR says he tried to warn other board members about problems with KiOR’s technology to turn wood chips into an oil substitute, claims that could damage the company’s defense in shareholder lawsuits and a Securities and Exchange Commission investigation.

KiOR denies Paul O’Connor’s claims, saying he was asked to leave the board after an investigation found he withheld a report from the company, talked to people outside the company without authorization and may have violated KiOR’s insider stock trading policy.