An American Senator in month of April 2013 introduced legislation in the US Congress which requires the sales of explosive powder be subject to a background check. The legislation was introduced in the wake of the Boston terror attack.
As per the Bill there should be a background check to purchase black powder, black powder substitute, or smokeless powder, in any quantity. It provides the Attorney General with the authority to stop the sale of explosives when a background check reveals that the applicant is a known or suspected terrorist and the Attorney General reasonably believes that the person may use the explosives in connection with terrorism.
It has been made illegal by the legislation to manufacture homemade explosives without a permit; and directs ATF to conduct a study on the tagging of explosives, particularly black powder, black powder substitute, and smokeless powder, which could enable law enforcement to detect, identify, and trace explosives used in crimes.
It is important here to note that the US Senator Lautenberg had introduced a similar proposal in 2003 as part of his Homeland Security Gun Safety Act of 2003.
As per the current law it is allowed for an individual to purchase as much as 50 pounds of explosive black powder without a background check, and also permits an individual to purchase unlimited amounts of dangerous smokeless powder and black powder substitute without a background check.
The powders can be used as the explosive material in assembling pipe bombs, used in the Columbine school shooting, and pressure cooker bombs, which were used in the recent Boston attack that left three persons dead and nearly 200 wounded.