shall be considered to be made to a section or other provi-
sion of the Internal Revenue Code of 1986.
SEC. 2. DEPRECIATION ADJUSTMENT USED IN COMPUTING
ALTERNATIVE MINIMUM TAXABLE INCOME.
(a) 150-PERCENT DECLINING BALANCE METHOD.—
(1) IN
GENERAL.—Paragraph (1) of section
56(a) (relating to depreciation) is amended to read
as follows:
‘‘(1) DEPRECIATION.—
‘‘(A) 150-PERCENT
DECLINING
BALANCE
METHOD.—
‘‘(i) IN
GENERAL.—In the case of
property not described in clause (ii), the
depreciation deduction allowable under sec-
tion 167 shall be determined as provided in
section 168(a), except that the applicable
depreciation 
method 
under 
section
168(a)(1) shall be—
‘‘(I) the 150-percent declining
balance method (200-percent declining
balance method in the case of com-
puter or peripheral equipment (as de-
fined in section 168(i)(2)(B)),
‘‘(II) switching to the straight
line method for the 1st taxable year
for which using the straight line
method with respect to the adjusted
basis as of the beginning of the year
will yield a higher allowance.
‘‘(ii) PROPERTY NOT USING 150-PER-
CENT
METHOD.—Property described in
this clause is section 1250 property (as de-
fined in section 1250(c)) or any other
property if the depreciation deduction de-
termined under section 168 with respect to
such other property for purposes of the
regular tax is determined by using the
straight line method.
‘‘(B) NORMALIZATION
RULES.—With re-
spect to public utility property described in sec-
tion 168(i)(10), the Secretary shall prescribe
the requirements of a normalization method of
accounting for this section.’’.
(2) NO ADJUSTMENT FOR ADJUSTED CURRENT
EARNINGS
SYSTEM.—Clause 
(i) 
of 
section
56(g)(4)(A) (relating to depreciation adjustments for
computing adjusted current earnings) is amended by
adding at the end the following new sentence: ‘‘The
preceding sentence shall not apply to property placed
in service in taxable years beginning after December
31, 1992, and the depreciation deduction with re-
spect to such property shall be determined under the
rules of subsection (a)(1)(A).’’.
(b) EXCEPTION FOR ENVIRONMENTAL PROPERTY.—
(1) IN GENERAL.—Section 56(a)(1) (relating to
depreciation adjustments), as amended by subsection
(a)(1), is amended by adding at the end the follow-
ing new subparagraph:
‘‘(C) ENVIRONMENTAL IMPROVEMENT AS-
SETS.—This paragraph shall not apply to envi-
ronmental improvement assets (as defined in
section 59(k)).’’.
(2) ENVIRONMENTAL IMPROVEMENT ASSETS.—
Section 59 (relating to definition and special rules)
is amended by adding at the end the following new
subsection:
‘‘(k) ENVIRONMENTAL IMPROVEMENT ASSETS.—
‘‘(1) IN
GENERAL.—For purposes of section
56(a)(1)(B), the term ‘environmental improvement
asset’ means tangible property which is—
‘‘(A) of a character subject to the allow-
ance for depreciation provided in section 167;
‘‘(B) used for, or is functionally related to
property used for, one or more of the following
purposes—
‘‘(i) source reduction,
‘‘(ii) solid waste minimization,
‘‘(iii) waste conversion or recycling,
‘‘(iv) reduction of environmental haz-
ards,
‘‘(v) compliance with environmental
permits, rules, and similar requirements,
including requirements with respect to
noise pollution such as the reduction of
aircraft noise level to stage 3 noise level
(as defined in 14 CFR § 36.1(f)(5)),
‘‘(vi) prevention, containment or con-
trol of unplanned releases, or
‘‘(vii) the manufacture, distribution
and sale of alternate fuels and blending
stocks or fuel additives for reformulated
fuels, and
‘‘(C) except in the case of property used
for the reduction of aircraft noise levels de-
scribed in subparagraph (B)(v), located and
used exclusively in the United States during the
taxable year.
If only a portion of property described in subpara-
graphs (A) and (C) is described in subparagraph
(B), such portion shall be treated as an environ-
mental improvement asset.
‘‘(2) OTHER
DEFINITIONS.—For purposes of
this subsection—
‘‘(A) SOURCE
REDUCTION.—The term
‘source reduction’ means reduction of the
amount of regulated substances or other pollut-
ants from fixed or mobile sources released into
the environment if such reduction reduces haz-
ards to public health or environment.
‘‘(B) SOLID
WASTE
MINIMIZATION.—The
term ‘solid waste minimization’ means the re-
duction in the generation of, or the recovery of
commercially usable products from, residual
materials which are classified as, or which if
disposed would be classified as, solid wastes
(within the meaning of the Resource Conserva-
tion and Recovery Act).
‘‘(C) 
WASTE
CONVERSION
OR
RECY-
CLING.—The term ‘waste conversion or recy-
cling’ means the processing or conversion of liq-
uid, solid, or gaseous wastes into fuel, energy,
or other commercially usable products, and the
production of such products if production oc-
curs at the same facility as the conversion.
‘‘(D) ABATEMENT
OF
ENVIRONMENTAL
HAZARDS.—The term ‘abatement of environ-
mental hazards’ includes the abatement, reduc-
tion, monitoring, or stabilization of potential
human exposure to toxic chemicals, hazardous
or extremely hazardous substances, or harmful
radiation.
‘‘(E) UNPLANNED RELEASES.—The term
‘unplanned releases’ means any release of regu-
lated substances (except federally permitted re-
leases), including indoor releases.
‘‘(F) REGULATED SUBSTANCE.—The term
‘regulated substance’ includes any substance
the release or emission of which is prohibited,
limited, or regulated by Federal or State law or
by Federal regulations (as determined without
regard to whether a particular release would
have been prohibited or limited).
‘‘(G) RELEASE.—The term ‘release’ means
any spilling, leaking, pouring, discharging, es-
caping, dumping, or disposing into the environ-
ment, including the abandonment or discarding
of barrels or other closed receptacles.’’.
(c) EFFECTIVE DATE.—The amendments made by
this section shall apply to property placed in service in
taxable years beginning after December 31, 1992.
SEC. 3. PRE-1993 MINIMUM TAX ALLOWED AS CREDIT
AGAINST MINIMUM TAX FOR CERTAIN TAX-
PAYERS.
(a) IN GENERAL.—Section 53(c) (relating to limita-
tion) is amended by adding at the end the following new
paragraph:
‘‘(2) SPECIAL RULE FOR CERTAIN TAXPAYERS
WITH PRE-1993 UNUSED MINIMUM TAX CREDITS.—
‘‘(A) IN GENERAL.—If a taxpayer had an
unused minimum tax credit for at least 3 of the
taxable years in the testing period, then, subject
to the limitation of subparagraph (B), the limi-
tation under paragraph (1) for any taxable year
following the testing period shall in no event be
less than 50 percent of the excess (if any) of—
‘‘(I) the tentative minimum tax
for such taxable year, over
‘‘(II) the sum of the credits al-
lowable under subparts A, B, D, E,
and F of this part.
‘‘(B) LIMITATION.—
‘‘(i) IN GENERAL.—The aggregate in-
creases in the limitation under paragraph
(1) by reason of subparagraph (A) shall
not exceed the pre-1993 unused minimum
tax credits.
‘‘(ii) ORDERING RULE.—For purposes
of clause (i), any credit under subsection
(a) for taxable years following the testing
period shall be treated as allocated to pre-
1993 unused minimum tax credits until
such credits are used up.
‘‘(C) DEFINITIONS.—For purposes of this
paragraph—
‘‘(i) TESTING
PERIOD.—The term
‘testing period’ means the 5-taxable year
period ending with the taxpayer’s last tax-
able year beginning in 1992.
‘‘(ii) PRE-1993 UNUSED MINIMUM TAX
CREDITS.—The term ‘pre-1993 unused
minimum tax credits’ means the credits al-
lowable under subsection (a) remaining un-
used as of the close of the testing period.’’.
(b) CONFORMING AMENDMENTS.—Section 53(c) (as
in effect before the amendment made by subsection (a))
is amended—
(1) by striking ‘‘The’’ and inserting:
‘‘(1) IN GENERAL.—Except as provided in para-
graph (2), the’’, and
(2) by redesignating paragraphs (1) and (2) as
subparagraphs (A) and (B).
(c) EFFECTIVE DATE.—The amendments made by
this section shall apply to taxable years beginning after
December 31, 1992.
SEC. 4. ALLOWANCE OF GENERAL BUSINESS CREDIT
AGAINST PORTION OF MINIMUM TAX.
(a) IN GENERAL.—Subparagraph (A) of section
38(c)(1) (relating to limitation based on amount of tax)
is amended by inserting ‘‘75 percent of’’ before ‘‘the ten-
tative minimum tax’’.
(b) EFFECTIVE DATE.—The amendment made by
this section shall apply to taxable years beginning after
December 31, 1992.
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