<PAGE>

                                                                  Exhibit 24.2.3

                          ARCO CHEMICAL TECHNOLOGY, LP

                                POWER OF ATTORNEY

     WHEREAS, ARCO CHEMICAL TECHNOLOGY, LP, a Delaware limited partnership (the
"Company"), an indirect wholly owned subsidiary of Lyondell Chemical Company
("Lyondell"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), a
Registration Statement on Form S-3, including one or more prospectuses, with
such amendment or amendments thereto, whether pre-effective or post-effective,
in each case as may be necessary or appropriate, together with any and all
exhibits and other documents having relation to said Registration Statement
(collectively, the "Registration Statement"), in connection with potential
future issuances of securities registered thereby by Lyondell, the Company or
their affiliate co-registrants.

     NOW, THEREFORE, the undersigned, in his or her capacity as a director or
officer, or both, as the case may be, of ARCO Chemical Technology Management,
Inc., the general partner of the Company, does hereby appoint Kerry A. Galvin
and T. Kevin DeNicola and each of them severally, his or her true and lawful
attorneys or attorney with power to act with or without the others and with full
power of substitution and resubstitution, to execute in his or her name, place
and stead, in his or her capacity as a director or officer or both, as the case
may be, of ARCO Chemical Technology Management, Inc., the general partner of the
Company, the Registration Statement and all instruments necessary or incidental
in connection therewith, with such amendment or amendments thereto in each case
as may be necessary or appropriate, together with any and all exhibits and other
documents relating thereto as said attorneys or any of them shall deem necessary
or incidental in connection therewith, and to file the same or cause the same to
be filed with the Commission. Each of said attorneys shall have full power and
authority to do and perform in the name and on behalf of the undersigned, in any
and all capacities, every act whatsoever necessary or desirable to be done to
the premises, as fully and to all intents and purposes as the undersigned might
or could do in person, the undersigned hereby ratifying and approving the acts
of said attorneys and each of them.

     IN WITNESS WHEREOF, the undersigned has executed this instrument on this
7th day of May, 2002.

                                /s/ Francis P. McGrail
                                -----------------------------------------------
                                FRANCIS P. MCGRAIL
<PAGE>

                          ARCO CHEMICAL TECHNOLOGY, LP

                                POWER OF ATTORNEY

     WHEREAS, ARCO CHEMICAL TECHNOLOGY, LP, a Delaware limited partnership (the
"Company"), an indirect wholly owned subsidiary of Lyondell Chemical Company
("Lyondell"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), a
Registration Statement on Form S-3, including one or more prospectuses, with
such amendment or amendments thereto, whether pre-effective or post-effective,
in each case as may be necessary or appropriate, together with any and all
exhibits and other documents having relation to said Registration Statement
(collectively, the "Registration Statement"), in connection with potential
future issuances of securities registered thereby by Lyondell, the Company or
their affiliate co-registrants.

     NOW, THEREFORE, the undersigned, in his or her capacity as a director or
officer, or both, as the case may be, of ARCO Chemical Technology Management,
Inc., the general partner of the Company, does hereby appoint Kerry A. Galvin
and T. Kevin DeNicola and each of them severally, his or her true and lawful
attorneys or attorney with power to act with or without the others and with full
power of substitution and resubstitution, to execute in his or her name, place
and stead, in his or her capacity as a director or officer or both, as the case
may be, of ARCO Chemical Technology Management, Inc., the general partner of the
Company, the Registration Statement and all instruments necessary or incidental
in connection therewith, with such amendment or amendments thereto in each case
as may be necessary or appropriate, together with any and all exhibits and other
documents relating thereto as said attorneys or any of them shall deem necessary
or incidental in connection therewith, and to file the same or cause the same to
be filed with the Commission. Each of said attorneys shall have full power and
authority to do and perform in the name and on behalf of the undersigned, in any
and all capacities, every act whatsoever necessary or desirable to be done to
the premises, as fully and to all intents and purposes as the undersigned might
or could do in person, the undersigned hereby ratifying and approving the acts
of said attorneys and each of them.

     IN WITNESS WHEREOF, the undersigned has executed this instrument on this 7
day of May, 2002.


                                     /s/ Eva Chu
                                     -------------------------------------------
                                     EVA CHU
<PAGE>

                          ARCO CHEMICAL TECHNOLOGY, LP

                                POWER OF ATTORNEY

     WHEREAS, ARCO CHEMICAL TECHNOLOGY, LP, a Delaware limited partnership (the
"Company"), an indirect wholly owned subsidiary of Lyondell Chemical Company
("Lyondell"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), a
Registration Statement on Form S-3, including one or more prospectuses, with
such amendment or amendments thereto, whether pre-effective or post-effective,
in each case as may be necessary or appropriate, together with any and all
exhibits and other documents having relation to said Registration Statement
(collectively, the "Registration Statement"), in connection with potential
future issuances of securities registered thereby by Lyondell, the Company or
their affiliate co-registrants.

     NOW, THEREFORE, the undersigned, in his or her capacity as a director or
officer, or both, as the case may be, of ARCO Chemical Technology Management,
Inc., the general partner of the Company, does hereby appoint Kerry A. Galvin
and T. Kevin DeNicola and each of them severally, his or her true and lawful
attorneys or attorney with power to act with or without the others and with full
power of substitution and resubstitution, to execute in his or her name, place
and stead, in his or her capacity as a director or officer or both, as the case
may be, of ARCO Chemical Technology Management, Inc., the general partner of the
Company, the Registration Statement and all instruments necessary or incidental
in connection therewith, with such amendment or amendments thereto in each case
as may be necessary or appropriate, together with any and all exhibits and other
documents relating thereto as said attorneys or any of them shall deem necessary
or incidental in connection therewith, and to file the same or cause the same to
be filed with the Commission. Each of said attorneys shall have full power and
authority to do and perform in the name and on behalf of the undersigned, in any
and all capacities, every act whatsoever necessary or desirable to be done to
the premises, as fully and to all intents and purposes as the undersigned might
or could do in person, the undersigned hereby ratifying and approving the acts
of said attorneys and each of them.

     IN WITNESS WHEREOF, the undersigned has executed this instrument on this 7
day of May, 2002.



                                      /s/ Laura C. Fulton
                                      -----------------------------------------
                                      LAURA C. FULTON
<PAGE>

                          ARCO CHEMICAL TECHNOLOGY, LP

                                POWER OF ATTORNEY

     WHEREAS, ARCO CHEMICAL TECHNOLOGY, LP, a Delaware limited partnership (the
"Company"), an indirect wholly owned subsidiary of Lyondell Chemical Company
("Lyondell"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), a
Registration Statement on Form S-3, including one or more prospectuses, with
such amendment or amendments thereto, whether pre-effective or post-effective,
in each case as may be necessary or appropriate, together with any and all
exhibits and other documents having relation to said Registration Statement
(collectively, the "Registration Statement"), in connection with potential
future issuances of securities registered thereby by Lyondell, the Company or
their affiliate co-registrants.

     NOW, THEREFORE, the undersigned, in his or her capacity as a director or
officer, or both, as the case may be, of ARCO Chemical Technology Management,
Inc., the general partner of the Company, does hereby appoint Kerry A. Galvin
and T. Kevin DeNicola and each of them severally, his or her true and lawful
attorneys or attorney with power to act with or without the others and with full
power of substitution and resubstitution, to execute in his or her name, place
and stead, in his or her capacity as a director or officer or both, as the case
may be, of ARCO Chemical Technology Management, Inc., the general partner of the
Company, the Registration Statement and all instruments necessary or incidental
in connection therewith, with such amendment or amendments thereto in each case
as may be necessary or appropriate, together with any and all exhibits and other
documents relating thereto as said attorneys or any of them shall deem necessary
or incidental in connection therewith, and to file the same or cause the same to
be filed with the Commission. Each of said attorneys shall have full power and
authority to do and perform in the name and on behalf of the undersigned, in any
and all capacities, every act whatsoever necessary or desirable to be done to
the premises, as fully and to all intents and purposes as the undersigned might
or could do in person, the undersigned hereby ratifying and approving the acts
of said attorneys and each of them.

     IN WITNESS WHEREOF, the undersigned has executed this instrument on this
7th day of May, 2002.

                                  /s/ Charles L. Hall
                                  ---------------------------------------------
                                  CHARLES L. HALL
<PAGE>

                          ARCO CHEMICAL TECHNOLOGY, LP

                                POWER OF ATTORNEY

     WHEREAS, ARCO CHEMICAL TECHNOLOGY, LP, a Delaware limited partnership (the
"Company"), an indirect wholly owned subsidiary of Lyondell Chemical Company
("Lyondell"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), a
Registration Statement on Form S-3, including one or more prospectuses, with
such amendment or amendments thereto, whether pre-effective or post-effective,
in each case as may be necessary or appropriate, together with any and all
exhibits and other documents having relation to said Registration Statement
(collectively, the "Registration Statement"), in connection with potential
future issuances of securities registered thereby by Lyondell, the Company or
their affiliate co-registrants.

     NOW, THEREFORE, the undersigned, in his or her capacity as a director or
officer, or both, as the case may be, of ARCO Chemical Technology Management,
Inc., the general partner of the Company, does hereby appoint Kerry A. Galvin
and T. Kevin DeNicola and each of them severally, his or her true and lawful
attorneys or attorney with power to act with or without the others and with full
power of substitution and resubstitution, to execute in his or her name, place
and stead, in his or her capacity as a director or officer or both, as the case
may be, of ARCO Chemical Technology Management, Inc., the general partner of the
Company, the Registration Statement and all instruments necessary or incidental
in connection therewith, with such amendment or amendments thereto in each case
as may be necessary or appropriate, together with any and all exhibits and other
documents relating thereto as said attorneys or any of them shall deem necessary
or incidental in connection therewith, and to file the same or cause the same to
be filed with the Commission. Each of said attorneys shall have full power and
authority to do and perform in the name and on behalf of the undersigned, in any
and all capacities, every act whatsoever necessary or desirable to be done to
the premises, as fully and to all intents and purposes as the undersigned might
or could do in person, the undersigned hereby ratifying and approving the acts
of said attorneys and each of them.

     IN WITNESS WHEREOF, the undersigned has executed this instrument on this
7th day of May, 2002.

                                   /s/ David J. Prilutski
                                   --------------------------------------------
                                   DAVID J. PRILUTSKI