Homegrown cannabis factories are generating massive profits for Irish and foreign gangs, with figures indicating growhouses uncovered by gardaí are capable of producing around €100m worth of the drug every year.
It is the first such estimate of a trade which has boomed in recent years, reflected in a tenfold rise in the amount of cannabis plants seized by gardaí between 2009 and 2012.
Cannabis production — once dominated by Chinese and Vietnamese gangs, but increasingly involving Irish and Eastern European outfits — is considered to offer profits greater than any other form of illegal drug.
Figures compiled by the Garda National Drugs Unit show that:
nThe number of plant seizures doubled from 253 in 2009 to 513 in 2012, with 311 in the first nine months of 2013;
nThe quantity of plants seized rose tenfold from 5,713 plants to 55,483, with 20,081 plants up to September last year;
nThe value of plants seized increased eightfold from €2.8m to €22.2m, with €16m worth seized to Sept 2013.
Figures provided to the Irish Examiner show the number of cannabis factories rose from 183 in 2011 to 226 in 2012, with 124 in the first nine months of last year.
The GNDU breaks down the factories, which are capable of producing a harvest in eight-to-12 weeks, into four scales of operations: medium, large, very large and industrial.
There has been a significant increase in industrial factories, from 11 in 2011 to 28 in 2012, with 11 up to September last year. The number of very large factories rose from 27 to 48, with 24 up to Sept 2013.
An analysis of the seizures show the industrial factories seized in 2012 and 2013 had on average a harvest of 1,300 plants. Based on a valuation of €800 per plant and five-to-six harvests in a year, the GNDU estimates such factories have the potential to produce approximately €5m-€6m worth of product annually.
This indicates the 11 industrial plants uncovered in 2013 had a potential capacity of between €57m and €68m worth of product a year. Applying the same process to very large, large and medium factories, this indicates an overall potential value of between €88m and €102m.
The figures are even larger in 2012, despite the lower official valuation of plants, at €400 each. The 2012 analysis suggests an overall potential valuation between €104m and €123m, with industrial plants making up €73m-€87m of that.
The estimates are based on growhouses that are uncovered and does not include undetected factories.
"Cannabis cultivation is a lucrative industry which is intrinsically linked to serious organised crime in this country," said Detective Sergeant Brian Roberts of the GNDU. "An Garda Síochána is committed to tackling the problem and targeting those involved."
He said gardaí have had "significant success" in detecting growhouses under a dedicated national operation, codenamed Nitrogen, established in 2007.
Unpublished figures from the Health Research Board show the number of people entering treatment for cannabis as their main problem drug reached 2,216 in 2012 (or 29% of all cases).
This compares with 2,086 in 2011, 1,519 in 2009 and 963 in 2007 (17% of all cases).