(a) The requirements in this subchapter apply to all municipal solid waste (MSW) landfill units or MSW facilities as defined in §330.5 of this title (relating to Classification of Municipal Solid Waste Facilities).(b) The owner or operator of all existing MSW landfill units or lateral expansions at a facility who is unable to comply with §330.545 of this title (relating to Airport Safety), §330.547 of this title (relating to Floodplains), or §330.559 of this title (relating to Unstable Areas), as applicable; shall complete final closure of the unit or facility by October 9, 1996, and conduct post-closure activities in accordance with §330.463(a) of this title (relating to Post-Closure Care Requirements).(c) The deadline for closure required by subsection (b) of this section may be extended up to two years if the owner or operator of the MSW landfill unit or MSW facility submits to the executive director for review and approval a request for an extension of the closure deadline that demonstrates to the satisfaction of the executive director that there is no alternative disposal capacity and there is no immediate threat to human health and the environment from the unclosed MSW landfill unit or MSW facility.(d) Permits that existed before the comprehensive rule revisions of this chapter adopted in 2006 became effective remain valid subject to the requirements of §330.401(b) of this title (relating to Applicability).