As several states continue to deal with fuel shortages a key source of gasoline has gone offline due to technical problems and the shortage of a fuel additive.

Production at the Antonio M. Amor refinery in Salamanca, Guanajuato, stopped Wednesday due to problems with the facility’s reformer units and a shortfall of the chemical additive MTBE.

According to sources inside the refinery, most of the site’s reformers are merely recirculating their supply while others are undergoing extensive repairs. Sources also say that lighting has been shut off in some parts of the complex.

The Salamanca refinery produces about 23,600 barrels of gasoline a day, 13% of Mexico’s total production.

Fuel from the refinery supplies the states of Guadalajara, Guanajuato, Durango, Nayarit, Jalisco, Colima and Michoacán, among others.

Sources told reporters that Pemex hopes to resume regular fuel production by February 9.