From the FBI website:http://www.fbi.gov/page2/dec06/employ_policy.htm
FBI MODIFIES PRE-EMPLOYMENT DRUG USE POLICY
12/21/06
Washington D.C.—Director Robert S. Mueller, III today announced a modification in the FBI's pre-employment drug policy. After a thorough review, the policy was modified to eliminate certain specific numeric thresholds as the sole determinant of suitability for employment in the FBI. Consistent with the approach taken by other Intelligence Community agencies, in making the determination about an applicant's suitability for FBI employment, all relevant facts, including the recency and frequency of use, now will be evaluated. Otherwise the pre-employment drug policy is unchanged.
The changes eliminate the focus on numeric thresholds, while maintaining the FBI's high standards. We have found the numeric thresholds to be arbitrary, not necessarily the key determinant of suitability for FBI employment. Too often, the focus of the inquiry into an applicant's background has centered on the number of incidents of usage, as opposed to the recency, context, as well as frequency, of prior usage. Further, where we have a numerical standard, the inquiry into suitability often turns on the applicant's ability to remember the exact number of uses as opposed to the pattern of usage. This focus makes the polygraph examination more difficult to administer.
This new policy will in no way alter or eliminate the FBI's rules of zero tolerance regarding drug usage for onboard employees. Any employee determined to have used illegal drugs while employed by the FBI will be referred to the Inspection Division and the Security Division for investigation and appropriate action."