That's an interesting point you make. Our engines have to meet all the U.S. Environmental Protection Agency standards that a diesel engine would, or a gasoline engine, for that matter. Whether it's a Ford F-250 or a forklift—we do forklift engines as well—or a locomotive, we have to meet all those minimum emissions criteria, and maximum emissions criteria, for that matter, that are prescribed by the United States Environmental Protection Agency and correspondingly adopted by the Canadian government. In the case of other jurisdictions, like China or South America or Europe, we meet the Euro standards. So we have to go through all the testing that a comparable diesel engine would go through to meet our emissions standards.
Historically, our natural gas engines have always either met or exceeded the emissions standards by quite a margin. Diesel engines have become progressively cleaner, with all the after-treatment systems that are being adopted by the diesel engine manufacturers to get their emissions down. Those would be criteria emissions, which are particulate matter, which is the soot that comes out of the tailpipe, and nitrogen oxides, which cause that yellow haze on the horizon when there's a lot of it. Those emissions standards have to be met by natural gas engines as well.
Our big emissions advantage today is on greenhouse gas emissions. Importantly, also, we don't have to use anywhere near the complexity of after-treatment equipment, typically, to achieve the same emissions level as a diesel engine, or exceed it, for that matter.