Pfizer’s Largest Manufacturing Plant in Kalamazoo, Michigan Dumped More than 1,000 Gallons of a Dangerous Toxic Chemical at the Plant Causing City Officials to Shut Down River Access Pfizer notified the City of Kalamazoo after it released more than 1,000 gallons of a toxic chemical and known carcinogen called Methylene Chloride at their manufacturing plant on Portage Rd. Now, the Kalamazoo Water Reclamation Plant is testing its wastewater for methylene chloride spilled into the sanitary sewer system by Pfizer this week, but results aren’t expected to be in until tomorrow, March 15th. OSHA considers methylene chloride to be a potential occupational carcinogen. The most common means of exposure to methylene chloride is inhalation and skin exposure, OSHA reports. Pfizer’s facility in Kalamazoo is also where Pfizer first mass produced its COVID-19 vaccine and where it is working on their new mRNA technology today.