TOPEKA, Kan. (AP) — An environmental group says companies engaged in an oil and gas drilling method known as fracking have used chemicals that can cause cancer in four wells in Kansas. Industry representatives on Wednesday denied the allegations in a report issued by the Environmental Integrity Project. The Topeka Capital-Journal reports the group says the chemicals used to extract gas from the four wells included kerosene, diesel and other hydrocarbons during hydraulic fracturing, or fracking. Katie Brown, a spokeswoman for a program of the Independent Petroleum Association of America, says the industry has adequate safeguards to protect public health. She also says permits to use kerosene weren't required when most of the wells were in use.