. G . R . ▁system . ▁ ▁As ▁of ▁ 2 0 1 7 , ▁bl ended ▁b iod ies el ▁fu els ▁( es pecially ▁B 5 , ▁B 8 , ▁and ▁B 2 0 ) ▁are ▁regularly ▁used ▁in ▁many ▁heavy - d ut y ▁vehicles , ▁especially ▁trans it ▁bus es ▁in ▁US ▁cities . ▁Character ization ▁of ▁exhaust ▁em issions ▁showed ▁significant ▁emission ▁redu ctions ▁compared ▁to ▁regular ▁dies el . ▁ ▁Material ▁compatibility ▁ ▁Pl ast ics : ▁High - dens ity ▁poly eth yl ene ▁( HD PE ) ▁is ▁compatible ▁but ▁poly vin yl ▁ch lor ide ▁( P VC ) ▁is ▁slowly ▁de grad ed . ▁Pol yst y rene ▁is ▁dissol ved ▁on ▁contact ▁with ▁b iod ies el . ▁ ▁Met als : ▁B iod ies el ▁( like ▁m eth an ol ) ▁has ▁an ▁effect ▁on ▁co pper - based ▁materials ▁( e . g . ▁br ass ), ▁and ▁it ▁also ▁affect s ▁z inc , ▁tin , ▁lead , ▁and ▁cast ▁iron . ▁ ▁St ain less ▁ste els ▁( 3 1 6 ▁and ▁ 3 0 4 ) ▁and ▁al umin um ▁are ▁una ffect ed . ▁ ▁Rub ber : ▁B iod ies el ▁also ▁affect s ▁types ▁of ▁natural ▁rub bers ▁found ▁in ▁some ▁older ▁engine ▁components . ▁Studies ▁have ▁also ▁found ▁that ▁flu or in ated ▁el ast om ers ▁( F K M ) ▁c ured ▁with ▁per ox ide ▁and ▁base -