The gasworks site, now home to gleaming new apartments, has been transformed. And beside it, a 1.1-hectare site is now home to a 200m development that includes a Clarion Hotel, O2's new Irish headquarters and apartments. But before anything could be built, there was a problem: ground contamination.

The area had once been home to a wood treatment business.

That provided listed consultancy business White Young Green, which has its headquarters in Leeds, with an opportunity. The company's Irish division was responsible for site remediation, ridding the area of accumulated toxic soil that was ultimately shipped to Belgium and the Netherlands for decontamination.

It's just part of the WYG's continued business expansion in Ireland. In June it acquired one of Ireland's largest chartered surveying firms, Nolan Ryan, for up to 19m. That brought WYG's total Irish acquisition costs to roughly 40m in the past five years. It now employs 450 people on the island. Last week WYG announced a 14% rise in revenue, net of payments to third parties, to £133m ( 192m) for the 12 months to the end of June.

Profit rose 24% to £11.6m ( 16.8m).

The work at sites such as that on Dublin's quays can be long and drawn-out. Michael Cunningham, managing director of WYG's environmental services division in Ireland, said the company began initial work in 2000 and it wasn't completed until 2004. Much of that time was absorbed with obtaining the necessary licences from the local authority and from the Environmental Protection Agency.

"We removed soil down to a depth of three metres, " explained Cunningham, "and then between three and eight metres there was contamination that required soil stabilisation."

That was necessary to stop any leeching or movement that could have resulted in odours emanating from the soil following construction.

A cement-based product was pumped into the soil that solved the problem, allowing building work to commence once the EPA had approved the remediation. In total, said Cunningham, a total of 67,000 tonnes of soil were shipped off-site to Belgium and the Netherlands.

"You want to be getting a ship in and out in 24 hours, or else you can incur higher port costs, " he added.

Somewhat bizarrely, there is no EU directive that specifically deals with site decontamination, he pointed out. That means that each EU member state has different rules on what is or isn't acceptable. Cunningham says that lightly contaminated soil that may once have gone to landfill here can now be used in road-building or landscaping in Holland, for instance.

More of the division's work is coming from the death of the petrol station. As swathes of such operations are wiped out to make way for apartments, WYG is finding itself busy.

Decontamination of such sites usually involves the introduction of bacteria that will break down any hydrocarbon residue.

Just 17% of WYG's revenue is currently generated on the island of Ireland, with income being almost evenly split between the Republic and Northern Ireland. Chief executive John Purvis told the Sunday Tribune last week that he views the company's commitment to Ireland as "permanent" and he wants to develop a sustainable business on the island. He added that additional acquisitions are likely in the next 12 months.

"We've been developing our business in Ireland for the past six years or so and we're not finished yet, " he said. He said he has been encouraged by the fact that much of the growth in the Irish business (revenue jumped 23% throughout the island last year) has been organic. "It's our fastest-growing geographical region, " said Purvis.

While keen to identify new takeover opportunities, Purvis added that WYG remains choosy. "We're looking at where we can generate value, " he said. "We don't just buy more of the same. We're always looking for how we can make one plus one equal three."

Key drivers for growth in the Irish market, according to Purvis, are continued spending on the national development plan as well as "increasing interest" in public-private partnerships, EU legislation, particularly in the context of water quality and environmental protection, and further investment associated with tourism and urban regeneration in Dublin and Belfast.