The BIA explained:

If an otherwise qualifying LPR is removable or deportable by virtue of a plea or conviction between Apr. 24, 1996 and Apr. 1, 1997, 212(c) relief is available unless: (1) proceedings were commenced on or after Apr. 24, 1996, and the conviction renders the applicant deportable under one or more of the deportability grounds enumerated in 440(d) of the AEDPA; or (2) the applicant is subject to the grounds of inadmissibility under sections 212(a)(3)(A), (B), (C), or (E), or (10)(C) of the Act; or (3) the applicant has served an aggregate term of imprisonment of at least 5 years as a result of one or more aggravated felony convictions entered between November 29, 1990 and Apr. 24, 1996. Id. at 272. Section 440(d) of AEDPA made the following classes of aliens ineligible for 212(c) relief: (1) aggravated felons; (2) those convicted of controlled substance offense; (3) those convicted of firearm offenses; (4) those convicted of specific miscellaneous crimes, such as espionage; and (5) those convicted of multiple CIMTs. AEDPA 440(d); see INA 212(c) (2005). An LPR who meets the 7 year domicile requirement and is removable or deportable by virtue of a plea or conviction entered before Apr. 24, 1996, is eligible to apply for discretionary relief under former section 212(c), however, the same grounds of inadmissibility apply.

Matter of Abdelghany, 26 I&N Dec. 254.
Thanks to Tamikka Pate at Crimmigration.com