Three men were injured in the blast at the premises on Plumpton Road in Hoddesdon, Hertfordshire, last October.
Two of them, Jashar Lamallari, 37, and Ardian Lamallari, 42, both from Wood Green, London, later died in hospital.
Simon Thomerson, 40, from Southerland Avenue in Maida Vale, London, has been charged with two counts of manslaughter by gross negligence.
He also faces charges of breaching health and safety laws.
More news from Hertfordshire
The explosion happened at about at 16:40 BST on 3 October.
At the time Hertfordshire Police said the unit was unoccupied, but it was believed the men had been carrying out some work on the building.
Mr Thomerson was released on bail and will appear before magistrates in St Albans on 16 August.

Wildlife enthusiasts had been watching the chicks and their mother and last saw them on the evening of 27 May.
However all of the birds, which can be sold for thousands of pounds, disappeared from their Sutton Bank nest in the North York Moors before 4 June.
North Yorkshire Police is investigating whether the disappearance was because of a predator or a criminal act.

NUS lawyers have written to Business Secretary Sajid Javid, demanding he properly considers the equality impact of the move.
Plans to scrap grants were announced by Chancellor George Osborne in his budget in July.
The government said it would respond to the letter in due course.
Currently, students whose family income is below £25,000 are eligible for full grants worth up to £3,387 plus a loan of £4,047 if they live away from home outside London.
Partial grants on a sliding scale are available for students whose family income is below £60,000.
The government wants to replace the grants with loans for new students from next year.
In its judicial review pre-action letter, the NUS identifies "a serious and unlawful failure" in the government to discharge a duty set out in the 2010 Equality Act to consider the impact of the policy on the poorest students.
"The abolition of maintenance grants will cause a very significant increase in debt for the poorest students; from £40,500 to around £53,000 at a time when the impacts of the 2012 recent reforms remain to be properly analysed and understood," says the letter.
NUS President Megan Dunn called the government's plan "reckless", citing "strong evidence" the change would mean higher education "becomes less accessible to minority groups".
She added: "We know the huge damage that this change will have if it is allowed to happen. It is obvious that the government is attempting to rush through these changes with no consideration on future generations of students."
Salima Budhani of legal firm Bindmans said the NUS was calling upon the secretary of state "to halt plans to abolish maintenance grants and to gather information to enable him to properly consider the complex equality considerations at stake.
"An open minded reconsideration of the policy should then take place."
A spokeswoman for the Department for Business Innovation and Skills said students would not have to pay back anything until their earnings rose above £21,000.
The maintenance loan for all students would also rise from next year to £8,200 for students living away from home outside London: "the highest amount of support ever provided", the spokeswoman added.
A man has been charged following the deaths of two brothers in an explosion at an industrial unit.
[NEXT_CONCEPT]
Three peregrine falcon chicks have gone missing from a nest in North Yorkshire, sparking a police investigation.
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The National Union of Students (NUS) has taken the first step in legal action over government plans to scrap maintenance grants in England.