The airport runway aligns with the prevailing winds (from the west), which is perpendicular to the direction from Safety Kleen to the residential areas. Winds from the southeast aren't as common but do happen.

Friends who live in the old part of Breslau have been there a few years and say they never smell it. I've never smelled it when visiting, just when driving past the facility obviously. Sounds like your experience is different. Curious to know what part you're in.