对某些环境性癌症隐患的证据有限不应该与证明无害混为一谈：相关研究比较困难，且在美国只有极少一部分受到政府和商业的资助。
The limited nature of evidence on some environmental cancer hazards should not be confused with proof that no harm has occurred: the research is hard to do, and, in the US, very little of it is now funded by the government and private sector.