The date of the enactment of this section, referred to in subsec. (c)(2), (4), is the date of enactment of Pub. L. 105–34, which was approved Aug. 5, 1997.

Sections 101(14), 102, 104, and 105(a)(8)(B) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, referred to in subsecs. (c)(2) and (d), are classified to sections 9601 (14), 9602, 9604, and 9605 (a)(8)(B), respectively, of Title 42, The Public Health and Welfare.

2006—Subsec. (d)(1)(C). Pub. L. 109–432, § 109(b), added subpar. (C).

Subsec. (h). Pub. L. 109–432, § 109(a), substituted “2007” for “2005”.

2004—Subsec. (h). Pub. L. 108–311 substituted “2005” for “2003”.

2000—Subsec. (c). Pub. L. 106–554, § 1(a)(7) [title I, § 162(a)], amended subsec. (c) generally. Prior to amendment, subsec. (c) defined the term “qualified contaminated site” to include certain property described in section 1221 (a)(1) of this title, within a targeted area, and at which there had been a release or disposal of any hazardous substance, provided that an area could be treated as a qualified contaminated site only if the taxpayer received a certain statement from an appropriate State agency, provided for designation of appropriate State agencies, and defined targeted area.

Subsec. (h). Pub. L. 106–554, § 1(a)(7) [title I, § 162(b)], substituted “2003” for “2001”.

1999—Subsec. (c)(1)(A)(i). Pub. L. 106–170, § 532(c)(2)(A), substituted “section 1221 (a)(1)” for “section 1221 (1)”.

Subsec. (h). Pub. L. 106–170, § 511, substituted “2001” for “2000”.

Pub. L. 109–432, div. A, title I, § 109(c), Dec. 20, 2006, 120 Stat. 2939, provided that: “The amendments made by this section [amending this section] shall apply to expenditures paid or incurred after December 31, 2005.”

Pub. L. 108–311, title III, § 308(b), Oct. 4, 2004, 118 Stat. 1179, provided that: “The amendment made by subsection (a) [amending this section] shall apply to expenditures paid or incurred after December 31, 2003.”

Pub. L. 106–554, § 1(a)(7) [title I, § 162(c)], Dec. 21, 2000, 114 Stat. 2763, 2763A–625, provided that: “The amendments made by this section [amending this section] shall apply to expenditures paid or incurred after the date of the enactment of this Act [Dec. 21, 2000].”

Amendment by section 532(c)(2)(A) of Pub. L. 106–170 applicable to any instrument held, acquired, or entered into, any transaction entered into, and supplies held or acquired on or after Dec. 17, 1999, see section 532(d) of Pub. L. 106–170, set out as a note under section 170 of this title.

Section 941(c) of Pub. L. 105–34 provided that: “The amendments made by this section [enacting this section] shall apply to expenditures paid or incurred after the date of the enactment of this Act [Aug. 5, 1997], in taxable years ending after such date.”