Section 44. Liability of employer

The  total compensation due shall be
  recoverable from the employer who last  employed  the  employee  in  the
  employment  to  the  nature of which the disease was due and in which it
  was contracted. If, however, such disease,  except  silicosis  or  other
  dust  disease and compressed air illness or its sequelae, was contracted
  while such employee was in the  employment  of  a  prior  employer,  the
  employer  who  is  made liable for the total compensation as provided by
  this section, may appeal to the  board  for  an  apportionment  of  such
  compensation  among  the  several employers who since the contraction of
  such disease shall have employed such employee in the employment to  the
  nature  of  which  the  disease  was  due.  Such  apportionment shall be
  proportioned to the time such employee was employed in  the  service  of
  such  employers, and shall be determined only after a hearing, notice of
  the time and place of which shall have  been  given  to  every  employer
  alleged  to be liable for any portion of such compensation. If the board
  finds that any portion of such compensation is payable  by  an  employer
  prior  to  the employer who is made liable for the total compensation as
  provided by this section, it shall make an award accordingly in favor of
  the last employer, and such award may be enforced in the same manner  as
  an award for compensation.