Nuclear power plants can be very health hazardous.  Risks stem from transportation and storage of radioactive materials and wastes, soil and groundwater contamination, and potential accidents resulting in the release of radioactive gases into the air.

Serious accidents are naturally the biggest concern associated with nuclear power plants.  Such accidents could send vast quantities of radiation into the surrounding air.  Smaller scale versions might also involve significant releases.  Because of this, nuclear power plants are required to have elaborate back-up systems to contain radioactive releases.

Storage and transportation of spent nuclear fuel has also caused major problems.  A permanent burial site for radioactive waste has never materialized, and temporary alternatives have left room for accidents and groundwater contamination.  Water left over from cooling nuclear reactors has caused problems as well, since this water often is disposed of in nearby bodies of water and can create a thermal impact.  Chromium, a toxic metal, was previously used in this cooling water, eventually causing much surface and groundwater to become contaminated with this toxin.

Any of the risks involved with nuclear power plants can greatly harm humans.  Exposure to high quantities of radiation, in cases of catastrophic accidents or even in the transportation of radioactive material, can cause anything from vomiting and skin disease, to cancers, genetic defects, and death.  Radiation releases by normal plant practices, however, do relatively little harm; such releases are less dangerous than an X-ray, and comparatively minor next to inhalation of radon.  However, the everyday operations of a nuclear power plant can contaminate groundwater; such contamination can become a major health threat both via human ingestion and via air contamination.