American Power Group Receives EPA Approval for 85 Additional OUL Vehicular Engines; Total OUL Approvals Now Cover 208 Engine Model Years for Six of the Most Popular OEM Engines

LYNNFIELD, MA--(Marketwired - Aug 12, 2013) - American Power Group Corporation (OTCQB: APGI), announced today that its subsidiary, American Power Group, Inc. ("APG"), has received online notification from the U.S. Environmental Protection Agency ("EPA") that its recent Clean Alternative Fuel Vehicle and Engine Conversion Submissions have been approved for the following Outside Useful Life ("OUL") engines:

• Detroit Diesel: Series 60; 11.1L to 14L; (2002-1987)
• Volvo/Mack: D11, D12, D13, D16, E7, MP7, MP8, MP10; 10.8L to 16.1L; (2009-2002)

The submissions utilized APG's V5000 Dual Fuel Turbocharged Natural Gas™ technology which is required to meet specific design, componentry, and emission compliance criteria per the EPA Final Rule 40CFR Parts 85 and 86.

Depending on the age and mileage of the targeted engine year to be converted, APG performs either an on-road emissions test to meet the OUL requirements or tests on an engine dynamometer for the more difficult Intermediate Useful Life ("IUL") requirements. An EPA engine family approval allows APG to commercialize that specific engine model conversion in the market without further emissions testing.

Lyle Jensen, American Power Group Corporation's Chief Executive Officer, stated, "This round of EPA approvals marks the completion of a majority of our Class 8 truck OUL emissions testing. We now offer fleet operators the broadest range of OUL Class 8 engine model conversions than anyone in the industry. These specific approvals open up the APG Detroit Diesel dual fuel glider kit market as previously announced on August 6^th and the Volvo-Mack engine families which are popular in the grocery and beverage distribution channels. Over the next few months, we expect to complete our submission for the one remaining targeted OUL engine family and seek approval of several additional engine models for the glider kit market."

Mr. Jensen further said, "Additionally, we continue to focus on our first EPA IUL approval which is nearing completion and then we will begin emissions testing on the top three to four 2010 - 2012 Selective Catalytic Reduction (SCR) technology engines which will open up the balance of the lower mileage addressable Class 8 truck market."

Mr. Jensen concluded, "APG is putting the foundation in place to facilitate a broad-base adoption of natural gas conversions for the North American Class 8 trucking industry. With current OUL and future IUL approvals for CAT, Cummins, Detroit Diesel, Mack, Mercedes Benz, and Volvo engines, and an estimated 3 million plus Class 8 engines on the road today, APG is in a unique position to address a multi-billion dollar market through our WheelTime Authorized Dealer and Certified Installer Network (www.WheelTime.com). The rate of adoption is in its early-stages but the trend is towards a large-scale shift to natural gas from diesel fuel."

APG will be participating in the upcoming Great American Truck Show in Dallas, Texas, on August 22-24, 2013, where both its CNG Dual Fuel Glider Kit and LNG Dual Fuel Glider Kit will be on display.

About American Power Group Corporation
American Power Group's alternative energy subsidiary, American Power Group, Inc., provides a cost-effective patented Turbocharged Natural Gas™ conversion technology for vehicular, stationary and off-road mobile diesel engines. American Power Group's dual fuel technology is a unique non-invasive energy enhancement system that converts existing diesel engines into more efficient and environmentally friendly engines that have the flexibility to run on: (1) diesel fuel and liquefied natural gas; (2) diesel fuel and compressed natural gas; (3) diesel fuel and pipeline or well-head gas; and (4) diesel fuel and bio-methane, with the flexibility to return to 100% diesel fuel operation at any time. The proprietary technology seamlessly displaces up to 80% of the normal diesel fuel consumption with the average displacement ranging from 40% to 65%. The energized fuel balance is maintained with a proprietary read-only electronic controller system ensuring the engines operate at original equipment manufacturers' specified temperatures and pressures. Installation on a wide variety of engine models and end-market applications require no engine modifications unlike the more expensive invasive fuel-injected systems in the market. See additional information at: www.americanpowergroupinc.com.

Caution Regarding Forward-Looking Statements and Opinions
With the exception of the historical information contained in this release, the matters described herein contain forward-looking statements and opinions, including, but not limited to, statements relating to new markets, development and introduction of new products, and financial and operating projections. These forward-looking statements and opinions are neither promises nor guarantees, but involve risk and uncertainties that may individually or mutually impact the matters herein, and cause actual results, events and performance to differ materially from such forward-looking statements and opinions. These risk factors include, but are not limited to, results of future operations, difficulties or delays in developing or introducing new products and keeping them on the market, the results of future research, lack of product demand and market acceptance for current and future products, adverse events, product changes, the effect of economic conditions, the impact of competitive products and pricing, governmental regulations with respect to emissions, including whether EPA approval will be obtained for future products and additional applications, the results of litigation, factors affecting the Company's future income and resulting ability to utilize its NOLs, and/or other factors, which are detailed from time to time in the Company's SEC reports, including the report on Form 10-K for the year ended September 30, 2012 and the Company's quarterly reports on Form 10-Q. Readers are cautioned not to place undue reliance on these forward-looking statements and opinions, which speak only as of the date hereof. The Company undertakes no obligation to release publicly the result of any revisions to these forward-looking statements and opinions that may be made to reflect events or circumstances after the date hereof or to reflect the occurrence of unanticipated events.