American Bar Association Model Rules of Professional Conduct - Rule 1.10. Imputation of Conflicts of Interest: General Rule
(a) While lawyers are associated in a firm, none of them shall knowingly represent a client when any one of them practicing alone would be prohibited from doing so by Rules 1.7 or 1.9, unless
(1) the prohibition is based on a personal interest of the disqualified lawyer and does not present a significant risk of materially limiting the representation of the client by the remaining lawyers in the firm; or
(2) the prohibition is based upon Rule 1.9(a) or (b) and arises out of the disqualified lawyer's association with a prior firm, and
(i) the disqualified lawyer is timely screened from any participation in the matter and is apportioned no part of the fee therefrom;
(ii) written notice is promptly given to any affected former client to enable the former client to ascertain compliance with the provisions of this Rule, which shall include a description of the screening procedures employed; a statement of the firm's and of the screened lawyer's compliance with these Rules; a statement that review may be available before a tribunal; and an agreement by the firm to respond promptly to any written inquiries or objections by the former client about the screening procedures; and
(iii) certifications of compliance with these Rules and with the screening procedures are provided to the former client by the screened lawyer and by a partner of the firm, at reasonable intervals upon the former client's written request and upon termination of the screening procedures.
(b) When a lawyer has terminated an association with a firm, the firm is not prohibited from thereafter representing a person with interests materially adverse to those of a client represented by the formerly associated lawyer and not currently represented by the firm, unless:
(1) the matter is the same or substantially related to that in which the formerly associated lawyer represented the client; and
(2) any lawyer remaining in the firm has information protected by Rules 1.6 and 1.9(c) that is material to the matter.
(c) A disqualification prescribed by this rule may be waived by the affected client under the conditions stated in Rule 1.7.
(d) The disqualification of lawyers associated in a firm with former or current government lawyers is governed by Rule 1.11.