A mandate for Massachusetts oil retailers to blend biofuel into the diesel and home heating oil they sell has been suspended, according to the Boston Globe.

Biofuel makers, distributors and sellers, who said their businesses will suffer without the state mandate, criticized the decision from the Massachusetts Department of Energy Resources. The requirement had been scheduled to take effect July 1.

State officials experienced complications in trying to write regulations for blending biofuel and said that initiating the regulations now would be too costly for businesses and consumers. The quota for using biofuel will be voluntary until the state can figure out how to make the program work.

Biofuel businesses said that since the mandate was passed in 2008, little has been done to put it into practice. A federal tax credit for using biofuels in conventional oil products cut the cost for biofuel consumers, but that credit expired in January, which a Department of Energy Resources official said put biofuels at a disadvantage.

On the other side of the issue is the trade group Massachusetts Petroleum Council, which has called the mandate ill-conceived and based on several of faulty assumptions, such as the continued existence of the federal subsidy.

But some groups such as the Massachusetts Oilheat Council believe the state will mandate use of biofuel, despite the delay.