The high stakes of emergent environmental crises, from climate change to widespread toxic exposures, have motivated STS practitioners to innovate methodologically, including leveraging STS scholarship to actively remake environmental scientific practice and technologies. This thematic collection brings together current research that transforms how communities and academics identify, study, and collectively respond to contaminants engendered by the fossil fuel and petrochemical industries, including air contamination from hydraulic fracking, marine pollution from petroleum-derived plastics, and hydrocarbon derivatives such as formaldehyde that intoxicate our homes. These interventions make inroads into the "undone science" and "regimes of imperceptibility" of environmental health crises. Authors, most of whom are practitioners, investigate grassroots methods for collaboratively designing and developing lowcost monitoring tools, crowdsourcing data analysis, and imagining ways of redressing toxicity outside of the idioms of science. Collectively, these articles work towards remaking how