The Initiative is sending the three of them to Ypres, in Belgium, precisely on... April 20, 1915. Their task is to steal a crate holding 5,730 cylinders of benzyl cyanide and bring it back with them. They may do this however they see fit, and will be given devices to disguise themselves to varying ranks within the German army, or any of the other armies involved with the encounter. Honestly, aside from the whole war thing, it's a pretty straightforward mission, with the two days - one evening and one full day - prior to the start of the battle being in place to allow them access to the crate prior to its pivotal role in the battle.

While the loss of the gas does substantially reduce the deaths suffered by predominantly the French and Canadian regiments, the more important aspect of the theft is the lack of hundreds of blinded French soldiers. Several of them went on to have more fulfilled lives after the war, but one in particular would go on to live one slightly more than what he would have had before. He did the stereotypical French thing - he went home and made love to his wife, ensured that he experienced the nice things in life, because he understood how short it could be, but it was one afternoon on the sidewalk, walking through the city with his lunch in hand, looking at the art being produced on the streets that became the moment he changed. He knew others who had been blinded in later battles, learned eventually of how close his own fate might have been, through the trickle-down of intelligence, and wound up creating an entire philosophy for the foundation of not only debriefing soldiers, but properly seeing to their aftercare in specific and individual manners. Of course, by the current timeframe, this has been diluted once again, so the only tangible result for the three is the acquisition of chemicals and the observation of the cinema getting an extra five films added to their 'recovered' inventory, but for centuries it aided veterans in ways they wouldn't have had otherwise.

But mostly the Initiative just wants the chemicals. That whole 'benefit of mankind' thing was more or less incidental.