Air conditioning and mechanical company GSC has laid off 22 employees as major construction projects on the Island dry up in the economic downturn.GSC said yesterday it provided two weeks notice to 22 tradesmen employed at the KEMH site last week.Of those employees, 12 were non-Bermudian and ten were Bermudian, the company said. And of the Bermudians five were plumbers, two apprentices and three helpers.GSC added that of the ten Bermudians given a two-weeks layoff notice last week only three had returned to work yesterday.GSC continues to have 24 tradesmen working at the KEMH site and has had up to 56 persons involved on site since the project began.The air conditioning and mechanical/maintenance sector has gotten increasingly competitive in Bermuda amid the construction downturn. And in January BAS launched HVAC/service startup Efficient Technologies, also offering Mitsubishi Electric Cooling and Heating solutions.