These concerns came to a head when more than 1000 workers held an angry meeting with union officials in the site canteen last Friday morning.
Laing O'Rourke issued a statement after the meeting saying that it was working within its agreement with BAA and the unions. It said that there would "always be ongoing discussion around some elements of the terms and conditions", but that the package offered to Terminal 5 workers was "groundbreaking".
It said: "The on-site support and welfare facilities for operatives are of an exceptional standard. NVQ training as well as basic literacy and IT skills training are available to all site workers."
The statement added that Laing O'Rourke's industrial relations package would set standards in pay, health and welfare and training for the whole of the construction industry.
According to a deal signed in January, skilled workers on the site can earn up to £55,000 and unskilled workers up to £31,000.
Local union officials will now report to their national officers on the outcome of the Friday meeting. One union insider said there was no prospect of a strike in the near future, as discussions were at an early stage. He said: "There is also some manoeuvring within the different unions on the site for members and that is why there could be some outspoken demands."
Some unions are thought to be taking a more aggressive line than others over the grievances in an attempt to recruit workers.
A forum of unions, contractors and BAA officials will negotiate the terms of the deal, which should boost pay for workers on large airport schemes.
Determined to deliver
Douglas, who was previously BAA group technical director, replaces John Stent. He will move to a new position within BAA that is to be announced later this year.
Douglas said he was delighted to take up the post and was determined to deliver the project with a good safety record, on time and within budget.