The growth of Toronto brought serious ecological problems to Whitchurch–Stouffville. Between 1962 and 1969, hundreds of thousands of litres per month of sulfuric acid, calcium hydroxide, and oil waste were poured into unlined Whitchurch–Stouffville dumps never designed as landfill sites and situated directly above the town's main aquifer. This was followed by years of solid waste from Toronto (1,100 tons per day in 1982). In the early 1980s, a group initially named "Concerned Mothers" found that the miscarriage rate in Whitchurch–Stouffville was 26% compared to the provincial average of 15%, and that the town had a high rate of cancer and birth defects. Though the Ministry of Environment was satisfied that the wells tested in 1974 and 1981 had negligible levels of cancer causing agents (mutagens), the town opposed the expansion of the "York Sanitation Site #4". Only after much grass-roots advocacy at the provincial level was the site ordered to close on June 30, 1983. In 1984 it was reported in the Legislative Assembly of Ontario that PCBs were found in well-water, and that 27,000 gallons of contaminated leachate per day were leaking from the site, threatening ground water quality.