Employees of the FDA are subject to certain restrictions once they leave Federal service. The post-employment restrictions are contained in Title 18, U.S.C., Section 207.
18 U.S.C. 207(a) - restricts former employees from representing another person or entity back to the Government, with the intent to influence, on a particular matter regarding specific parties* in which they were personally and substantially involved.** This is a lifetime prohibition.
18 U.S.C. 207(b) restricts former employees from representing another person or entity before the Government, with the intent to influence, on a particular matter involving specific parties that was pending under their supervision during their last year of service.
18 U.S.C. 207(c) - is an additional restriction that applies to "senior employees." This restriction is known as the "One Year Cooling Off Period." This restriction prohibits former senior employees from contacting their former agency, with the intent to influence, on the behalf of anyone seeking official action. This restriction applies to any matter pending with the agency and is not limited to particular matters regarding specific parties in which the former employee was personally and substantially involved.
The Summary of Post-Employment Restrictions gives an overview of the restrictions under title 18 U.S.C. 207.
* The term "particular matter involving specific parties" encompasses only matters that involve deliberation, decision, or action that is focused upon the interests of specific persons, or a discrete and identifiable class of persons. The phrase includes investigations, applications, controversies, claims, charges, arrests, or judicial or other proceedings. The phrase does not include general rulemaking, legislation, or policy issues that are directed to the interests of a large and diverse group of persons.
** The phrase "personally and substantially involved" means direct participation as a Government employee through decision, approval, disapproval, recommendation, the rendering of advice, investigation, or other direct participation in a matter. It includes the direct and active supervision of the participation of a subordinate in a matter. Substantiality is based not only on the effort devoted to a matter, but also on the importance of the effort. A crucial step in a matter may not involve a lot of time, but it may be substantial in terms of impact.