From the employer's point of view, the uniform is supposed to look sharp. Achieving that with a pure organic cotton involves the added expense and energy burden of ironing. Once again, organic cotton's success in the uniform market...including success with lowering life cycle inputs all around... would hinge on altering the aesthetic expectation of customers, and re-defining what image the employer wishes to convey to it's customers.
As in the graphic, woolen twills are still used in uniforms for police, train conductors, bus drivers, and tradesmen who do a considerable amount of their work out of doors. Luckily, unlike cottons, good woolens will hold a crease. But in today's commercial buildings with central heating, woolen uniforms are long gone due to the combined impact of cost and discomfort in the heat.
Put these ideas together, add a dash of imagination, and you can envision specially designed organic cotton uniforms fitting into some new scenes. Long term, a sea change in apparel preferences could come about if petroleum prices and feedstock availability became so problematic as to force people to dress in early 19'th Century style woolens and cotton under-wraps. As we enter the era of "Peak Oil" fashion and thermostat settings, organic clothing will be cost competitive as well as comforting.
We do know of one supplier of fine woolen outdoor "uniforms" who deserves serious TreeHugger attention. Although they don't feature organic fibers per se, they've been around since 1897 and for much of the intervening period pretty much defined the woolen or cotton uniform for serious outdoorsmen and loggers. The product line is still awesome. For a look at what we'll be wearing when Peak oil takes out the polyesters, we recommend the Filson Catalog.
For the crowning glory of woolen uniform hats we recommend the legendary Kromer Blizzard Cap, pictured here in red (available in other colors and "brimless"). According to this history of the Kromer Cap, one wag is reported to have said to its new maker: "It's the finest hat to wear on a Harley in the fall..." Since its origins in railroading are pretty much gone, the Kromer is still great for Elmer Fudd imitations and practicing dueling banjos. Seriously, ears that work outdoors love the Kromer and it'd fit right in on the Peak Oil runway.