As the precision of the tests increase, eventually everything will cause cancer. They found common things caused cancer once they could measure parts per thousand, then more things at parts per million, pretty soon when we can measure part per trillion or quadrillian or septillian and octillian or whatever, they will find carcinogens in everything.
Most folks really worry about certain things, but its more like the tv show Monk, there is bad stuff litteraly everywhere! Something I just learned... people get super concerned about radiation from nuclear power plants (I grew up within sight of one) but what few people know is that a coal power plant puts out more radiation and nuclear particles into the environment in one year than several nukes will in thier whole lifetime, to the point were you could fuel several nuclear plants from nuclear waste from coal plants if there existed better methods to extract them. Quoted from useless facts and information stored in my brain.