A future that once looked rosy for climbing ethanol blends with gasoline in Mexico could be in 

jeopardy as legal challenges to a new fuel regulation have found traction in court. 

A Mexican  federal  judge  has  issued  an  injunction against raising the amount of ethanol in 

gasoline  sold  in  most  of the country after a lawsuit was introduced arguing the increase will 

exacerbate  air  pollution problems, said Juan Machado, a partner in the law firm SOLCARGO 

and the attorney leading the case. The lawsuit also argues expert and environmental entities' 

opinions were not taken into account, Machado said in an interview with S&P Global Platts. 

"The  increase of ethanol in gasoline will produce a counterproductive effect on air quality by 

increasing  the emissions of volatile  organic  compounds," said Carlos Del Razo, a plaintiff in 

the case and an environmental lawyer. 

The  case  was  brought  by environmental activists, including former Mexican presidential ca 

ndid ate Gabriel Quadri. 

In 2016, the Mexican Energy  Regulatory  Commission (CRE) said it would allow ethanol blen 

ding  to  increase  to  5.8%  from  zero, as part of NOM-016, a broader measure to update its 

gasoline specifications. Then, in June of this year, the CRE announced it would be allowed at 

10%. 

NEW RULE PUT ON HOLD 

However, last week the federal judge granted the injunction against the regulation  that allow

d ethanol  blending  to  increase  to 10%  in  all  areas  except  Mexico City, Guadalajara and 

Monterrey. 

"We  are  concerned about extending vapor pressure waivers  because there are many more 

cities  that  present  problems  of  tropospheric  ozone  and poor air quality, even much more 

serious problems than Mexico City," Del Razo said about the measure. 

Increasing  the  amount  of  ethano in gasoline increases the Reid Vapor Pressure of the fuel, 

meaning it will evaporate more easily. In the US, gasoline with 10% ethanol received a waiver 

as it would have lower emissions despite the easier evaporation. 

Mexico uses MTBE as its primary oxygenate in gasoline, which is why ethanol has not been a 

consideration. 

The injunction says ethanol blending has to remain at 5.8% while the case is decided, which 

could take more than a year, according to Machado. 

"Our intent is not to stop energy reform but to demand that the judge forces the CRE not to 

ignore  the  environmental  variables that are very important in a country that is heavily poll 

uted," Machado said.