Compressed natural gas (CNG) interests have made recent advancements in fueling as well as engine technology.

Clean truck maker Greenkraft Inc. and bi-fuel conversion kit maker Impco Automotive both gained nationwide certification from the U.S. Environmental Protection Agency (EPA). Greenkraft also was certified by the California Air Resources Board.

Southern California-based Greenkraft obtained the dual certifications for its CNG or propane-powered engines, which are used on its own trucks and any power by General Motors’ 6.0-liter engine. Greenkraft offers both Isuzu NPR trucks converted to run on CNG or propane, and its own vehicles based on imported chassis.

Greenkraft Sales Director Frank Ziegler said “our system is completely tested and has undergone extreme conditions to ensure product durability and road validation.”

Similarly, Impco reported that its CNG-gasoline bi-fuel Ford F-150 pickup for the 2016 model year now has EPA certification. The half-ton truck features Ford’s 5.0-liter Ti-VCT (twin independent variable camshaft timing) V8 engine.

Impco is offering a “working class” pickup, including dedicated CNG and bi-fuel F-250 and F-350 pickups, along with larger, dedicated CNG Ford F-650 and F-750 trucks. The certifications cover sales in all 50 states for both companies.

Elsewhere, the push for CNG heavy-duty truck fleets continued in Chicago, Nebraska and Florida, where advanced fueling systems are becoming more common.

For Chicago’s Gold Standard Transportation, McNeilus Truck & Manufacturing has designed and installed range-extending back-of-cab CNG fuel cylinder units. The project involved the addition of a single, vertically mounted Type IV CNG tank on Kenworth tractors already fitted with rail-mounted CNG assemblies.

Gold Standard officials said McNeilus has installed complete CNG systems on four trucks and provided custom installations to add 19 diesel gallon equivalent (DGE) fuel capacity on two others. “The additional capacity eliminated the need for these trucks to require a fuel stop,” said Gino Fortuna, president of the trucking company, adding that the 19 DGE of additional capacity amounts to a 20% increase.

In Nebraska, Omaha’s Papillion Sanitation has started deploying CNG-fueled garbage trucks with help from the local Metropolitan Utilities District. A first truck is in service and three more are due in the next six months, the company said.

Papillion’s Jay Hannen, maintenance manager, said “CNG is the future and we wanted to be the first to bring it to Omaha.” The CNG refuse trucks have McNeilus bodies and Mack Truck chassis, fueling at a locally operated Trillium CNG station.

Another fleet operator in Florida, NFI, launched a new fleet of 12 CNG trucks last month to serve a national home improvement retailer in the region. The fleet is made up of Freightliner Cascadias with CNG fuel systems by Quantum Fuel Systems.

NFI said it is spreading its use of natural gas transportation to the Southeast. It deployed its first CNG trucks in Los Angeles in 2012. Gain Clean Fuel has opened a CNG fueling station in Kissimmee, FL, just south of Orlando, to support NFI’s Florida fleet.

NFI is using CNG in five trucks in California, 17 in Texas and 13 in Pennsylvania, along with the dozen in Florida.

Along with Gain’s new stations, other CNG fueling establishments are scheduled to open near Denver, and to be upgraded in the Los Angeles suburb of San Fernando.

Sapp Bros Inc. and Stirk CNG will open a public access CNG station in Commerce City, CO, southwest of Denver on Jan. 15. It will offer service to all types of natural gas vehicles, but will focus on Class 8 trucks, the companies said. The station, at an existing Sapp Bros Travel Center, is located at the intersection of two interstate highways (70 and 270).

In San Fernando, the city’s public works department has begun work to upgrade an eight-year-old CNG fueling station that supports city trolley and school buses, and refuse and street sweeping vehicles.

The project will include the “design, engineering, fabrication, installation, commissioning, testing and training” associated with the CNG station equipment upgrades, according to public works management analyst Kenneth Jones. A bidding process is scheduled to run Jan. 20 through Feb. 17.