Five former Linc Energy executives have been charged with environmental offences.

The Queensland Government announced charges will be laid over the failed company's alleged contamination of giant areas of prime farmland in the state's south-east.

The contamination was allegedly caused by Linc Energy's underground coal gasification (UCG) operation near Chinchilla from 2007 to 2013.

Linc Energy's founder and former chief executive Peter Bond had already been charged with three indictable offences of failing to ensure compliance with the Environmental Protection Act, but has now been summonsed on two new charges, along with four other former Linc executives.

The company, which is in liquidation with estimated debts of $300 million, faces five charges of wilfully and unlawfully causing serious environmental harm.

Reports say Queensland Government investigations in 2015 unveiled hundreds of square kilometres of prime agricultural land that is at risk from toxic chemicals and explosive gases allegedly seeping from Linc's UCG site.

Soil near the facility is allegedly permanently acidified, with claims that methane, hydrogen, carbon monoxide and hydrogen sulphide have leaked from the site.

Court committal proceedings last year heard workers had been exposed to “significant concentrations” of gases, and that some had claimed they fell ill after being exposed at the site.

The company denies the charges, but will stand trial when a date is set.

The new summonses mean Mr Bond, will be joined by four former Linc Energy executives; Donald Schofield (former Linc Energy general manager, on two charges), Stephen Dumble (former chief operating officer, on two charges), Jacobus (Kobus) Terblanche (former chief operating officer, on one charge) and Daryl Rattai (former general manager, on one charge).

Penalties for individuals convicted of the offences can face up to five years' jail, while the total maximum penalty for the charges against Linc Energy is $8,850,000.

Hearings at the Dalby Magistrates Court begin on November 29.

“Queensland's Environment Department is continuing its formal investigation into the activities of Linc Energy and it's possible more charges could be laid,” Environment Minister Steven Miles told reporters.

“As investigations remain active, and as this matter is now before the courts, the Government won't comment further on the details of the current charges.”