Exhibit 3.13

                            ARTICLES OF INCORPORATION

                                       OF

                            ENVIRONMENTAL REHAB, INC.
                            (a Wisconsin Corporation)
                           ---------------------------

                  These Articles of Incorporation are executed by the
undersigned for the purpose of forming a Wisconsin corporation under the
Wisconsin Business Corporation Law, Chapter 180 of the Wisconsin Statutes.

                                   ARTICLE I.

                                      Name

                  The name of the corporation is Environmental Rehab, Inc.

                                  ARTICLE II.

                                     Purpose

                  The purpose for which this corporation is organized is to
engage in any lawful activity within the purposes for which corporations may be
organized under the Wisconsin Business Corporation Law, Chapter 180 of the
Wisconsin Statutes.

                                  ARTICLE III.

                                  Capital Stock

          A. The aggregate number of shares which this corporation shall have
authority to issue is 56,000 of a single class designated as "Common Stock,"
having a par value of $1.00 per share.

          B. No shareholder of the corporation shall have any preemptive or
other subscription rights nor be entitled, as of right, to purchase or subscribe
for any part of the



unissued stock of this corporation or of any additional stock issued by reason
of any increase in authorized capital stock of this corporation or other
securities, whether or not convertible into stock of the corporation.

                                  ARTICLE IV.

                        Limitations on Transfer of Stock

          The transferability of any of the stock of the corporation may be
restricted from time to time by the shareholders by appropriate provision in the
by-laws or by agreement or agreements entered into by any shareholder or
shareholders with the corporation and/or any other shareholder or shareholders,
and/or with any third persons, and the shares of stock of such shareholder or
shareholders thereupon shall be subject to such by-laws, agreement or agreements
and shall be transferable only upon proof of compliance therewith; provided,
however, that such by-laws, agreement or agreements shall be filed with the
corporation and reference thereto placed on the certificate or certificates of
stock.

                                   ARTICLE V.

                           Registered Office and Agent

          The registered office of the corporation is located at 222 West
Washington Avenue, Madison, County of Dane, Wisconsin 53703 and the name of the
registered agent at such office is CT Corporation System.

                                   ARTICLE VI.

                                    Directors

          The number of directors may be fixed from time to time by the by-laws
but shall not be less than the minimum number allowed by Wisconsin law. The
directors need not be



shareholders and officers need not be directors. The initial Board of Directors
shall consist of three (3) members whose names are set forth below:

                                  P. Ralph Helm
                                Frank E. Stevens
                               G. Michael Decker

                                  ARTICLE VII.

                                  Incorporator

          The Incorporator is Thomas E. Lange, whose address is 111 East
Wisconsin, Suite 2100, Milwaukee, Wisconsin 53202.

                                 ARTICLE VIII.

                        Purchase of Shares by Corporation

          The corporation is authorized by action of the Board of Directors,
without the consent of the shareholders, to purchase, take, receive or otherwise
acquire shares of the capital stock of the corporation, subject to the
applicable provisions of Wisconsin law.

                                  ARTICLE IX.

                                    Recording

          This document shall be recorded in Dane County, Wisconsin.