State of California
AIR RESOURCES BOARD
The Biltmore hotel
515 S. Olive Street
Los Angeles, CA
July 7, 1977
77-16-1 Public Hearing Regarding Proposed Regulations
Restricting the use of Fuel Additives Containing
Manganese in Unleaded Gasoline.
ITEM NO.: 77-16-1
Public Hearing Regarding Proposed Regulations Restricting the use
of Fuel Additives Containing Manganese in Unleaded Gasoline.
Adopt Resolution 77-39, which modifies Title 13, California
Administrative Code, to suspend the use of manganese fuel
additives, such as MMT, in the unleaded grades of gasoline sold
in California until such time as the Board concludes that these
additives can be used so as not to adversely affect air quality.
Staff analysis of the available data on the effects of the
gasoline additive methylcyclopentadienyl manganese tricarbony1
(MMT) indicates that, when this additive is used in unleaded
gasoline, significant increases in vehicle hydrocarbon emissions
result. Problems involving catalyst plugging, spark plug
fouling, higher ambient sulfate concentrations, and increased
public exposure to toxic manganese compounds also are associated
with the use of MMT. The State Department of Health has advised
the staff that the increased use of manganese fuel additives
represents a potential health hazard.
Based on a status report on MMT presented at its April 28, 1977
meeting, the Board adopted Resolution 77-27 which requested all
refiners of gasoline sold in California voluntarily phase out the
use of MMT. The Board also directed the staff to schedule a
public hearing for the consideration of a regulation controlling
the use of MMT.
Since the staff's April 28 report, a workshop has been held to
discuss with oil refiners the feasibility of suspending the use
of MMT in unleaded gasoline. Although the oil industry clearly
would prefer to use MMT to minimize its productions costs, no
refiner, given 60 days notice, would experience an immediate
inability to meet market demand if regulations requiring a
suspension of the use of manganese fuel additives in unleaded
gasoline were adopted.
Most refiners claimed, however, that potential gasoline
availability problems would result by 1979-81 if they could not
rely on the use of MMT at that time. It appears to the staff
that sufficient lead time is available to meet gasoline demand
without the use of MMT. There are no technological problems
associated with producing 91 Research Octane unleaded fuel
without the use of MMT; however, refiners may have to modify
their facilities to some extent.
No Board action regarding the use of manganese fuel additives in
leaded gasoline is recommended at this time. The staff does not
have data which indicate that these additives increase emissions
from vehicles using leaded fuel. Increased atmospheric manganese
oxide concentration due to the use of manganese fuel additives in
leaded gasoline is considered a lesser problem since the use of
leaded fuel in California is rapidly decreasing.