A depiction of the molecular structure of one type of hydroflourocarbon, floating in front of a blue sky.


Hydro­flu­o­ro­car­bons (HFCs) are potent green­house gas­es that are used pri­mar­i­ly in refrig­er­a­tion and air con­di­tion­ing sys­tems. The Envi­ron­men­tal Pro­tec­tion Agency (EPA) and lead­ing com­pa­nies have iden­ti­fied the avail­abil­i­ty of safer alter­na­tives that do not have HFCs’ adverse cli­mate effects. Fol­low­ing a for­mal rule­mak­ing process that con­firmed the fea­si­bil­i­ty of HFC sub­sti­tutes, the EPA pro­hib­it­ed the use of HFCs in cer­tain prod­ucts in a rule that was final­ized in 2015. Attor­neys gen­er­al have insist­ed in the courts, rule­mak­ing process­es, and in Con­gress that the Agency reduce HFC emissions.

Urg­ing Rever­sal of a Deci­sion Toss­ing the 2015 Rule


  • August 2017

    The HFC rule was chal­lenged in court and, in August 2017, the D.C. Cir­cuit Court of Appeals issued a split deci­sion hold­ing that the EPA did not have the author­i­ty under Title VI of the Clean Air Act to stop man­u­fac­tur­ers from using dam­ag­ing HFCs in their prod­ucts. The rule was remand­ed to the EPA for fur­ther pro­ceed­ings. A coali­tion of 10 state attor­neys gen­er­al filed an ami­cus brief request­ing that the full Court of Appeals rehear the case, giv­en the nation­al and inter­na­tion­al ram­i­fi­ca­tions of the split deci­sion on the Clean Air Act’s author­i­ty to address this impor­tant cli­mate change issue.

  • Jan­u­ary 2018

    In Jan­u­ary 2018, the D.C. Cir­cuit denied the en banc hear­ing request. 

  • July 2018

    In July 2018, Mass­a­chu­setts Attor­ney Gen­er­al Mau­ra Healey and a coali­tion of 17 oth­er attor­neys gen­er­al filed an ami­cus brief in sup­port of a peti­tion by chem­i­cal pro­duc­ers and nation­al envi­ron­men­tal groups request­ing Supreme Court review of the D.C. Circuit’s deci­sion. The brief argues that the peti­tion should be grant­ed because the deci­sion under­mines states’ abil­i­ty to effec­tive­ly reduce human health and envi­ron­men­tal risks while dis­re­gard­ing the plain text of the Clean Air Act.

  • Octo­ber 2018

    In Octo­ber 2018, the Supreme Court declined to review the D.C. Cir­cuit deci­sion, deny­ing the peti­tion for cer­tio­rari by chem­i­cal pro­duc­ers and nation­al envi­ron­men­tal groups.

Chal­leng­ing EPA’s Roll­back of 2015 Rule


  • April 2018

    Fol­low­ing the D.C. Circuit’s denial of the en banc hear­ing request on the 2015 rule in Jan­u­ary 2018, the EPA, in April 2018, issued a guid­ance doc­u­ment stat­ing that it would not enforce the 2015 rule and instead would ini­ti­ate a notice-and-com­ment rule­mak­ing process in response to the remand. 

  • June 2018

    In June 2018, New York Attor­ney Gen­er­al Bar­bara Under­wood and a coali­tion of 11 attor­neys gen­er­al filed suit against the EPA for effec­tive­ly rescind­ing the 2015 rule by declin­ing to enforce the rule. The suit points out that the EPA unlaw­ful­ly adopt­ed the non-enforce­ment pol­i­cy through guid­ance rather than the notice-and-com­ment process as required by law.

  • April 2020

    In April 2020, the D.C. Cir­cuit ruled in favor of the attor­neys gen­er­al in find­ing that the EPA’s 2018 guid­ance doc­u­ment was a rule that was improp­er­ly issued with­out adher­ing to notice-and-com­ment require­ments. Con­se­quent­ly, the court vacat­ed the guid­ance doc­u­ment and remand­ed the mat­ter to EPA for fur­ther pro­ceed­ings con­sis­tent with the court’s decision.

Sup­port­ing Leg­is­la­tion to Reduce HFCs


  • April 2020

    In April 2020, now New York Attor­ney Gen­er­al Leti­tia James led a coali­tion of 11 attor­neys gen­er­al in sub­mit­ting a let­ter to the Sen­ate Envi­ron­ment and Pub­lic Works Com­mit­tee in sup­port of leg­is­la­tion that would reduce HFC emis­sions. The let­ter expressed sup­port for the Amer­i­can Inno­va­tion and Man­u­fac­tur­ing Lead­er­ship Act, which would facil­i­tate the phase out of HFCs. The attor­neys gen­er­al wrote that adop­tion of the leg­is­la­tion would ensure that the U.S. joins the glob­al effort to phase down HFCs, pro­vid­ing enor­mous cli­mate ben­e­fits through reduc­tion of cli­mate change-caus­ing emis­sions and cre­at­ing over 30,000 Amer­i­can man­u­fac­tur­ing jobs by pro­duc­ing HFC-free refrig­er­a­tion and air con­di­tion­ing systems.

  • Decem­ber 2020

    In Decem­ber 2020, Con­gress passed a spend­ing and COVID-19 relief pack­age, which includ­ed mea­sures to phase down HFCs. The mea­sures, orig­i­nal­ly intro­duced as the Amer­i­can Inno­va­tion and Man­u­fac­tur­ing (AIM) Act and agreed to in Sep­tem­ber 2020, will phase down pro­duc­tion and use of HFCs by 85 per­cent over 15 years. The com­pro­mise lan­guage also includes a nar­row clause that pre­empts new state reg­u­la­tions for cer­tain uses of HFCs for five years if replace­ments for cer­tain appli­ca­tions do not become wide­ly available.

Oppos­ing Weak­ened Appli­ance Standards


  • Octo­ber 2018

    In Octo­ber 2018, the EPA pub­lished a pro­posed rule rolling back appli­ance main­te­nance and leak repair require­ments for equip­ment using HFC refrig­er­ants hat had been adopt­ed via a 2016 rule. The EPA jus­ti­fied its pro­pos­al on a mod­est reduc­tion on indus­try com­pli­ance costs, while down­play­ing the increase in HFC emissions.

  • Novem­ber 2018

    In Novem­ber 2018, Mass­a­chu­setts Attor­ney Gen­er­al Healey and Cal­i­for­nia Attor­ney Gen­er­al Xavier Becer­ra led a coali­tion of six­teen attor­neys gen­er­al in sub­mit­ting com­ments on the pro­posed HFC refrig­er­ant rule. The com­ments called the pro­posed rule arbi­trary and capri­cious because the pro­pos­al lacks a ratio­nal con­nec­tion between the facts and the EPA’s deci­sion to relax HFC emissions.

  • March 2020

    In March 2020, the EPA, ignor­ing the objec­tions of the attor­neys gen­er­al, final­ized the rule, rolling back main­te­nance and leak repair require­ments for appli­ances using HFC refrig­er­ants. Two months lat­er, in May 2020, New York Attor­ney Gen­er­al James led a coali­tion of eleven attor­neys gen­er­al in fil­ing a peti­tion for review chal­leng­ing the law­ful­ness of the March 2020 final rule.

  • Octo­ber 2020

    In Octo­ber 2020, the coali­tion of attor­neys gen­er­al led by New York Attor­ney Gen­er­al James and an envi­ron­men­tal non­prof­it filed their ini­tial open­ing brief chal­leng­ing the March 2020 rule. The brief not­ed that the March 2020 rule imper­mis­si­bly rests on EPA’s mis­tak­en con­clu­sion that the Clean Air Act did not sup­port the issuance of the 2016 rule, which the agency claimed man­dat­ed the roll­back of the 2016 rule. Instead, EPA’s 2016 rule was a rea­son­able inter­pre­ta­tion of the Clean Air Act that fur­thered the pur­pose of the rel­e­vant Clean Air Act pro­vi­sion. Accord­ing­ly, the attor­neys gen­er­al stat­ed that the roll­back rule must be vacat­ed because it relied on an erro­neous legal conclusion.

  • Decem­ber 2020

    In Decem­ber 2020, the EPA filed its proof brief in the lit­i­ga­tion. The EPA argued that it rea­son­ably con­clud­ed that the Clean Air Act did not pro­vide it with the author­i­ty to issue the 2016 rule, while its March 2020 rule is con­sis­tent with the text of the Clean Air Act.