Final answer:
Certain materials that are hazardous, illegal, or violative of federal law cannot be sent through USPS. This includes items that could be used for bioterrorism, such as certain bacteria and viruses, as well as materials violating copyright laws, are obscene, or are threats.
Step-by-step explanation:
The United States Postal Service (USPS) prohibits the sending of certain materials that are considered hazardous, illegal, or violative of federal law. Information that poses a biohazard, such as sending certain bacteria or viruses, cannot be mailed due to the possible implications for bioterrorism. The USPS and the Federal Bureau of Investigation (FBI) take precautions against this by installing x-ray generators that irradiate suspicious mail. While x-rays can kill bacteria and some viruses, they also chemically alter the mail’s composition, affecting color, texture, and smell, but not making the mail radioactive. It is also illegal to mail any material that violates copyright law, is obscene, or constitutes a threat.
Moreover, in terms of information privacy, the USPS may collect metadata about items sent through the mail. Such metadata includes the time, location, sender, and recipient of the messages, but not their content. While collected anonymously, metadata can sometimes be traced back to individuals due to predictable patterns of communication and travel. However, content that infringes upon the privacy of individuals through illicit means or intended for illegal activities should never be sent via USPS.