Two CFMEU bosses could face criminal charges over the destruction of evidence demanded by the royal commission into trade unions.
Counsel assisting the commission has recommended Queensland Construction, Forestry, Mining and Energy Union secretary Michael Ravbar and former union state president David Hanna be charged over the removal and destruction of tonnes of union documents.
The documents were disposed of in April last year, on the same day the CFMEU was served with a notice from the commission to produce them.
"The commission should find that Mr Ravbar and Mr Hanna's conduct was done with an intention to conceal the removal and destruction of documents," was the recommendation at the commission says.
Both men testified at the commission last month and blamed each other for trying to cover up the destruction of the material.
Both said it was the other's idea to cover security cameras during a massive but "normal" clean-out of the CFMEU's Brisbane office on the same day it was served with the notice to produce evidence.
"A lot of organisations clean out, a lot of organisations shred stuff," Mr Ravbar told the commission in September, accusing Mr Hanna of stupidity and corrupt behaviour.
"The only thing that was unusual (was) about the stupidity of covering it up and the stupidity of the way it was removed."
Mr Hanna, who's since quit the union, insisted Mr Ravbar was behind the secrecy, denied suggestions he was trying to bring his old boss down, and accused him of ruling the union by fear.
Both men denied seeing the notice to produce evidence - which was emailed at 4.16pm on April 1, 2014 - until at least the following day, and insisted nothing of relevance was thrown out anyway.
CFMEU training coordinator Bob Williams earlier told the commission how he and fellow official Brian Humphrey were ordered to torch about 80 boxes of material in a paddock at then-divisional president Mr Hanna's Cornubia property, south of Brisbane.
"They're so squashed together, it doesn't burn very well, so we decided that was futile. We rang David and said ... 'We need to find another method to get rid of this stuff'," Mr Williams said.
The boxes were eventually loaded onto a hired tip truck bound for the dump, the load weighing in at 6.86 tonnes.
The commission was told there was a large amount of old material to get rid of, due to a recent merger with the Builders Labourers Federation, but no one could explain why Mr Hanna ordered an official to cover the building's security cameras with banners and an old T-shirt while the files were being cleaned out.