Both Environment-friendly and Environmentally-friendly are not only correct, but in fact required, so they're both bound to show up on google.
It's like this:
Where the packaging is for a product that involves a further assemblage / process / is in the DIY category- like an aerosol spray can of paint, for example- the usage environmentally-friendly is good. This here means Using this product or kit according to the recommended procedure will not seriously damage the planet.
The paint in the can itself might be environment-friendly, if it has so much lead, so much tin, so much phosphorous, and so on. This here means This product will not damage the environment. (Well, 'not any more than we're legally permitted to' at least.)
The former is for a process of some sort, and the latter, for a product where no further assembly or DIY or priming is involved; you simply open and consume (use up) the contents.
"Made using environmentally-friendly manufacturing practices" is one way to standardize, but it's sometimes inconvenient to print lengthy mandatories on a small packaging area.Also, this sometimes says nothing of the product itself, in which case it might turn out that the actual import is "this product contains an alarming abundance of ozone-depleting substances, but it happens to be manufactured using an approved process in a state-of-the-art setup that conforms to the European standard."
In some cases it's also sometimes tough to take a call on which is more correct. Is an "electric car" environmentally-friendly, or is it environment-friendly? There's as much semantics in R&D as in marketing & advertising.Company A might claim the former, while Company B might object. And while the government, the companies and the scientists go about interminably to reach a consensus, marketing and Q3 targets cannot wait. So, a convenient eco-friendly is used instead. This doesn't make it explicit if it means ecologically-friendly, or ecology-friendly, so the guys in legal like it. It's also shorter, so adland likes it.Run with it.
Between the two usages, environmentally-friendly carries the greater risk of morphing into This improves the environment, while environment-friendly just may or may not be factual, where provable.
Then again, with a product like packaged organic compost for your garden, you could use either, or perhaps even both, and it'd still ring/be true.
The contextual relevance of when either usage becomes significant with respect to a product also differs with different product categories - for a can of paint, it might be when the spraying is being done, for a battery it might be when after it runs out of juice and is discarded. For a synthetic food product, it might be when you're actually eating it as well as after you've eaten it. and so on.
Speaking for myself, I'd any day prefer a battery that claims to be environment-friendly, not environmentally-friendly.