Relative Toxicity Analysis

Relative  Toxicity  Analysis  of  Alternative  Chemicals  in  Hair  Products  using  P2oASys   Introduction   The  Boston  Public  Health  Commission  has  been  conducting  an  investigation  into  the   chemicals  that  make  up  the  active  ingredients  in  many  hair  relaxers  and  straighteners.   These  chemicals,  speci>ically  the  relaxing  agents,  have  known  human  health  impacts  that   are  of  particular  concern  not  only  to  the  consumers  of  the  products,  who  are  largely  black   women,  but  also  to  salon  workers  who  may  be  exposed  to  higher  levels  of  these  products.   BPHC’s  ongoing  work  is  to  identify  alternatives  to  these  products  that  do  not  contain   chemicals  that  carry  the  same  level  of  toxicity  and  human  health  impacts,  and  to  be  able  to   con>idently  recommend  these  products  as  replacements  for  those  currently  in  use.     The  Boston  Public  Health  Commission,  and  previous  directed  study  groups   identi>ied  chemicals  of  concern  in  typical  hair  relaxing  products  that  were  of  particular  risk   to  human  health.  BPHC  and  previous  directed  study  groups  also  identi>ied  products  that   market  themselves  as  safer,  less  toxic  alternatives  that  presumably  do  not  contain  the   chemicals  of  concern.  Material  Safety  Data  Sheets  were  collected  for  these  products  and   examined  to  identify  what  chemicals  are  being  used  as  the  replacement  relaxing  agents  in   these  products.  These  alternative  chemicals  can  be  compared  to  their  “typical”   counterparts  to  determine  whether  they  are  in  fact  less  toxic,  verifying  that  these  products   are  safer  alternatives.   The  purpose  of  this  directed  study  was  to  characterize  the  relative  toxicity  of  these   alternative  chemicals  compared  the  chemicals  used  in  regular  products.    Six  major   chemicals  of  concern,  as  well  as  three  alternative  chemicals,  were  selected  and  assessed   using  the  tool  P2oASys.  Part  of  this  study  included  exploring  P2oASys  as  a  tool  for  toxicity   comparison,  both  for  the  ongoing  work  on  this  issue,  and  for  future  studies.   Methods  and  Data   P2oASys   P2oASys  is  a  tool  developed  by  the  Toxics  Use  Reduction  Institute  to  assess  the   relative  toxicity  and  health  and  environmental  impacts  of  chemicals  and  methods  based  on   quantitative  and  qualitative  factors.  Information  about  the  chemicals  can  be  input  by  a  user   either  using  P2oASys  own  format  or  in  the  format  of  standard  Safety  Data  Sheets.    Information  may  be  inputted  regarding  several  categories,  including  physical  and  chemical   properties,  ecological  impacts,  exposure  control,  toxicological  information,  and  hazard   identi>ication.  As  the  purpose  of  our  study  was  to  assess  the  relative  risks  for  human  use,   the  latter  three  categories  were  of  particular  importance.    We  chose  to  use  the  SDS  format   for  inputting  chemical  information.       For  each  piece  of  information  that  is  input,  the  matrix  assigns  a  score  based  on  the   hazards  presented  by  that  characteristic  of  the  chemical.  Scores  are  tallied  at  the  end,  and   adjusted  based  on  the  other  chemicals  being  compared  and  a  relative  score  is  calculated.   This  score  can  be  used  to  make  assessments  about  the  relative  risks  of  each  chemical  in   question.     P2oASys  includes  additional  functions  that  allow  for  comparison  of  “mixtures”,  that   is,  the  relative  scores  for  combinations  of  chemicals  that  are  input  into  the  matrix.  These   tools  will  also  allow  for  comparison  of  toxicity  based  on  concentrations  of  chemicals  in  the   mixture,  which  would  be  useful  for  our  assessment  of  products  as  often  multiple   “strengths”  of  a  product  are  available  that  have  different  concentrations  of  the  chemicals  in   question.  However,  at  this  time,  as  P2oASys  is  in  beta,  the  mixture  tool  is  not  fully  functional   and  could  not  be  used  for  our  assessments.       Chemicals  Assessed   A  total  of  nine  chemicals  were  input  into  the  matrix  for  comparison,  six  of  which  are   chemicals  of  concern  often  found  in  typical  products,  and  three  are  chemicals  found  in   “alternative”  products.       • Sodium  Hydroxide  and  Calcium  Hydroxide   Sometimes  referred  to  as  “Lye”,  sodium  Hydroxide  is  used  most  commonly  in  hair   relaxers.  There  are  signi>icant  health  risks  and  concerns  associated  with  even  short-­‐term   exposure  to  sodium  hydroxide  (“Sodium  Hydroxide  (Lye)  Safety”).  It  is  one  of  the  chemicals   of  concern  that  should  be  replaced.     Calcium  hydroxide  is  often  used  as  a  replacement  for  sodium  hydroxide,  particularly  in   products  that  market  themselves  as  “lye  free”  (“Types  of  Relaxers”).  Though  technically  not   lye,  it  is  very  similar  to  sodium  hydroxide,  and  carries  many  of  the  same  safety  concerns  as   sodium  hydroxide.   • Ammonium  Hydroxide,  Ammonium  Thioglycolate,  and  Cysteamine   Ammonium  Hydroxide  and  Ammonium  Thioglycolate  appear  together  in  both   straightening  and  curling  perms.   Cysteamine  products  are  often  cited  as  an  alternative  to  ammonium  perms.  It  is   typically  used  for  curling  hair,  but  straightening  products  using  cysteamine  do  exist   (Malhotra,  2016).  However,  there  have  been  reports  of  these  products  not  being  as  effective   as  their  ammonium-­‐based  counterparts.     • Formaldehyde  and  Glyoxylic  Acid Formaldehyde  is  used  in  keratin  based  straightening  and  curling  products.  Once  the   keratin  breaks  bonds  in  the  hair,  formaldehyde  “locks-­‐in”  the  new  texture.  The  health  risks   associated  with  formaldehyde  exposure  are  severe.  Many  products  have  begun  to  use   Glyoxylic  Acid  and  similar  chemicals  as  alternatives  (McConnell,  2017).  However,  while   relative  toxicity  may  be  lower,  glyoxylic  acid  has  been  shown  to  release  formaldehyde  when   heated,  which  is  the  usual  protocol  for  most  keratin  hair  treatments.     • Propylene  Glycol  and  Phenoxyethanol Propylene  glycol  and  Phenoxyethanol  are  not  used  as  relaxing  agents.  They  appear  in   many  relaxing  “kits”  in  the  products  used  pre  or  post  hair  relaxing.  Phenoxyethanol  is  used   as  a  preservative  in  many  cosmetic  products  (“Phenoxyethanol”),  while  Propylene  glycol  is   used  as  a  conditioning  agent  (“Propylene  Glycol”).  They  are  included  here  as  they  appear  in   numerous  “alternative”  products  and  may  be  of  concern.     Inputting  information  into  the  matrix   Information  about  each  chemical  was  retrieved  from  Material  Safety  Data  Sheets.   Due  to  differences  in  the  MSDS  formats,  sometimes  multiple  were  referenced  for  each   chemical.  A  full  list  of  all  MSDS’  referenced  is  included  at  the  end.   Image  1  is  of  the  format  to  input  information  for  each  chemical.  Once  a  new  chemical   assessment  is  created  (in  this  case  sodium  hydroxide  is  being  used  as  an  example)  and  an   MSDS  or  other  source  of  information  is  found,  the  sections  can  be  expanded  and   information  can  be  input  into  each  subsection.    In  this  case,  the  categories  match  sections   on  a  standard  MSDS.  Image  2  is  of  the  expanded  “Hazards  Identi>ication”  section  which   shows  what  chemical  characteristics  are  included.  Information  does  not  have  to  be  input   into  every  single  subsection.  Subsections  that  don’t  have  information  input  are  not  counted   in  the  total  score  for  the  chemical.     (Image  1:  P2oASys  data  entry,  SDS  format)     (Image  2:  P2oASys  data  entry,  SDS  format,  expanded  Hazards  identi>ication  category)   In  the  case  of  our  example,  Sodium  Hydroxide  has  a  GHS  H  phrase  314  (found  on  its   SDS)  for  dermal  irritation.  The  subsection  includes  a  drop  down  menu  to  select  from  the   different  categories  and  H  phrases  (image  3).  Different  subsections  have  various  formats   for  inputting  information  that  match  standard  SDSs.     Once  information  is  input,  the  matrix  assigns  a  score  from  1  to  10,  10  being  the  highest.    This  subsection  score  is  then  used  in  the  >inal  calculation  of  scores  for  chemicals  (image  4).       (Image  3:  P2oASys  sample  format  for  data  entry  for  subsection)   (Image  4:  P2oASys  sample  data  entry  and  scores  for  subsection)   Results  and  Discussion   Matrix  Results   For  each  set  of  chemicals,  the  >inal  matrix  scores  are  shown  as  well  as  the  expanded   “Acute  Human  Effects”  category  that  shows  the  subsection  scores.  The  full  matrixes  for  each   set  of  chemicals  are  included  at  the  end  of  the  report  as  excel  >iles.     • Sodium  Hydroxide  and  Calcium  Hydroxide   (Image  5:  P2oASys  total  matrix  scores,  Sodium  Hydroxide,  Calcium  Hydroxide)     Sodium  hydroxide  received  a  score  of  8.7,  while  calcium  hydroxide  received  a  score  of   8.3.  The  overall  score  for  calcium  hydroxide  is  only  slightly  lower  than  that  of  sodium   hydroxide,  and  although  some  of  the  scores  for  acute  human  effects  were  lower  for  calcium   hydroxide,  other  scores  (dermal  irritation,  eye  irritation),  were  suf>iciently  high  as  to  be  of   concern.  This  indicates  calcium  hydroxide  is  not  signi>icantly  lower  in  terms  of  toxicity  than   sodium  hydroxide,  and  should  not  be  considered  a  safer  alternative.     • Ammonium  Hydroxide,  Ammonium  Thioglycolate,  and  Cysteamine   (Image  6:  P2oASys  total  matrix  scores,  Ammonium  Hydroxide,  Ammonium  Thioglycolate,   Cysteamine)     Cysteamine  has  a  much  lower  overall  score  compared  to  both  Ammonium  Hydroxide   and  Ammonium  Thioglycolate.  The  scores  for  the  acute  human  effects  for  Cysteamine  are   also  lower.  Notwithstanding  its  effectiveness  as  a  straightener,  Cysteamine  may  be  a  viable   safer  alternative  to  ammonium-­‐based  products.     •   Formaldehyde  and  Glyoxylic  Acid (Image  7:  P2oASys  total  matrix  scores,  Formaldehyde,  Glyoxylic  Acid)     Glyoxylic  Acid  and  Formaldehyde  have  the  same  overall  score,  though  the  category   scores  for  the  chemicals  are  slightly  different.  Glyoxylic  acid  has  signi>icantly  high  scores  for   certain  subsections  under  acute  human  effects,  which  makes  it  a  nonviable  alternative  to   formaldehyde,  even  when  disregarding  the  potential  for  secondary  formaldehyde   production.     • Propylene  Glycol  and  Phenoxyethanol   (Image  8:  P2oASys  total  matrix  scores,  Propylene  glycol,  Phenoxyethanol)     Propylene  Glycol  has  a  relatively  low  score,  which  means  it  may  be  prudent  to   dismiss  as  a  chemical  of  concern  when  it  appears  in  products.  Phenoxyethanol  has  a  higher   score,  both  overall  and  in  certain  categories  of  acute  human  effects.  There  may  be  cause  to   be  concerned  if  and  when  this  chemical  appears  in  products.     Conclusion     There  are  a  number  of  limitations  to  the  analysis  conducted.  The  scoring  in  the   matrix  is  limited  to  what  information  is  available  about  each  chemical  and  what  is  input   into  the  matrix.  The  information  available  for  each  chemical  is  not  uniform;  some  have   much  more  speci>ic  hazards  listed  in  their  SDS’  than  others,  and  some  hazard  metrics  may   be  more  relevant  to  assessment  of  human  health  impact  than  others.  In  order  to  combat   this  limitation,  multiple  sources  can  be  consulted  for  information  on  each  chemical,  as  was   done  for  many  of  the  chemicals  in  this  assessment.  Current  use  of  the  P2oASys  tool  is  also   made  dif>icult  as  assessments  cannot  be  saved  and  returned  to  at  a  later  time.  Each  time  the   tool  is  used,  a  new  assessment  must  be  created  and  the  information  about  each  chemical   inputted  again.  This  can  limit  the  number  of  chemicals  that  can  be  put  into  a  single  matrix   and  compared  to  one  another,  as  all  the  chemical  information  would  have  to  be  inputted  in   a  single  session,  which  poses  a  challenge  for  the  user.     As  mentioned  previously,  P2oASys  is  currently  in  beta  so  it  is  not  possible  to   compare  mixtures  of  chemicals  or  concentrations  of  chemicals.  This  is  of  particular  concern   as  the  concentrations  of  the  chemicals  vary  greatly  from  product  to  product.    Future   research  could  use  these  aspects  of  the  tool  as  they  become  fully  functional  to  do  more   thorough  comparisons  effects  of  chemical  mixtures  on  overall  toxicity.     Overall,  two  potential  replacement  chemicals,  calcium  hydroxide  and  glyoxylic  acid,   were  dismissed  as  viable  alternatives  for  their  more  common  counterparts.  Cysteamine  was   identi>ied  as  a  potentially  less  toxic  alternative  that  warrants  further  investigation  into  its   more  speci>ic  human  health  and  exposure  impacts  as  well  as  its  effectiveness  in  products.     This  paper  also  demonstrates  one  application  of  the  P2oASys  tool  as  a  method  of   preliminary  comparison  of  chemical  hazards  in  products,  particularly  in  narrowing  down   and  identifying  which  chemicals  should  be  researched  as  viable  alternatives.  This  paper   provides  a  guideline  for  how  this  kind  of  comparison  can  be  conducted,  not  only  for   chemicals  in  hair  relaxers,  but  also  for  any  kind  of  consumer  product.