Mack Truck Industry News

Mack to Deliver 120 Natural Gas-Powered
Trucks to

Waste Management, Inc.

LEHIGH VALLEY, Pa. (Sept. 25, 2000) - Mack Trucks, Inc., has reached an
agreement with longtime customer Waste Management, Inc. (NYSE: WMI) that will
put 120 natural gas-powered Mack® MR and LE Series trucks into service in
southern California.

The first vehicle has been delivered to the Waste Management facility in El Cajon,
Calif., where the giant refuse hauler announced that the company has joined forces
with PG&E Corporation (NYSE: PCG) to establish a program that will use emission
reductions gained from the vehicles to pave the way for construction of a power
plant in San Diego County. This is the first time that emission reductions from mobile
sources have been used to offset emissions from a major stationary source.

The vehicles will be equipped with the new 12-liter Mack Eco-Tech™ engine. With
325 horsepower and 1,050 ft. lb. of torque @ 1,250 RPM, these engines feature a
spark-ignited design and operate on either liquefied or compressed natural gas
(LNG or CNG). In order to meet the stringent emissions requirements requested by
Waste Management, the engines had to meet an EPA-certified NOx emissions level
of 2.0 grams per brake horsepower-hour (g/BHP-hr), which is 20 percent below
the EPA requirement that will go into effect in 2002.

Commenting on the new vehicles, Vince Fortuna, vice president of fleet services for
Waste Management, said, "The foundation for our agreement with PG&E
Corporation was based upon Mack delivering one of the cleanest engines in the
world today. When we presented this challenge to Mack, they not only achieved the
goal, but they also exceeded it - and with plenty of engine torque and power to do
the work that we require."

"Mack's pioneering work with alternative-fueled engines continues to gain
widespread acceptance in the trucking industry," added Scott Freeman, vice
president - national accounts for Mack. "These newest vehicles, which feature yet
another new engine design for a specific application, are one more example of
Mack's willingness and ability to give our customers what they need."

A total of 30 Mack LNG-powered vehicles will be delivered through this year, with
Waste Management agreeing to purchase another 90 vehicles over the next two
years.

Freeman added that the engines also are electronically controlled and feature clean,
quiet operation and maximum fuel economy, while running reliably at high operating
temperatures typical in trucks that travel at low speed for extended periods.

The control system of the 12-liter Mack Eco-Tech engine, engineered specifically to
accommodate the use of natural gas, consists of newly designed head and valve
covers to incorporate centrally located spark plugs. Additionally, valve seats also
have been hardened to minimize valve recession; throttling losses have been reduced
to improve part-load fuel economy; and a closed-loop, lean-burn control system
enhances overall operation and response.

When integrated into the Mack MR and LE chassis, the engine is fueled by two
LNG tanks that are mounted on each side of the truck - one holding 100 gallons and
the other holding 50 gallons. Waste Management also has the option to order a
single LNG fuel tank that would be mounted to the left rail and store 150 gallons of
fuel.

Dedicated to quality, reliability, and total customer satisfaction, Mack Trucks, Inc.
has provided innovative, forward-thinking products and services to its customers
worldwide for a century. Part of the global Renault V.I./Mack Group, Mack is one
of North America's largest producers of heavy-duty trucks, in addition to major
product components; the company also markets a line of medium-duty diesel trucks
across North America. Through the MackPower™ business unit, Mack
manufactures, markets and supports a line of diesel engines for commercial,
industrial and marine applications. MACK vehicles are sold and serviced in more
than 45 countries worldwide.