It shouldn't hurt you, but it has been burned by overheating during the drying process. If you dry you herbs slowly, preferably with natural air-circulation, they shouldn't go brown - they should retain a lot of their original colour and flavour. Of course, you need to start off with very fresh herbs in perfect condition before you dry them. A brown-dead leaf will have lost all those essential oils which give it its flavour.

It would help to know what method you used to dry your basil. Also how long ago you dried it - if there's been any moisture getting into the containers, or the basil wasn't completely dry before storing it, (nice and crispy-crumbly) that's an invitation for mould and fungi, in which case you should toss your basil out.

Personally, though I rarely have to do it, I think basil is one herb that is better to be frozen, rather than dried.

I just hung the basil upside down from the stalks, in my kitchen, away from direct sunlight. It started to turn brown even before it got completley dry and crispy. I think it took about 3-4 weeks to get completley dry.
It seems like the general consensus is that freezing basil works better than drying. I guess i'll try that next year - live and learn, right?

Basil has very volitile oils and thus doesn't work all that well dried.

Is what you have safe? No reason it shouldn't be. If it were mouldy you would see it. Basil tends to turn brown and rusty as it dries, anyway.

Rub some of the dried leaves in the palms of your hands, and smell it. If it still smells basily, then use it. But the flavor won't last all that long, so use it fairly quickly.

Basil really does preserve better when frozen.

Drying slowly, basil will turn brown and lose a lot of flavor. This is the main reason I usually say that a dehydrator that can dry these things quickly, also helps to retain color and flavor.

You dried it in your kitchen. Where the temperature can get very hot, especially if you hung your bunches anywhere near the stove, or your electric jug, or your microwave.... Take a good look on the top of your cupboards. You'll see that they are not only dusty, they're greasy. That's because grease particles fly around in a kitchen! They'll get onto your drying herbs, too. A kitchen is not a good place for drying herbs, unless it's a very large area with plenty of fresh air circulating. Equally, a laundry or bathroom is not a good place to dry herbs, because of the moisture in such areas. If you have a covered verandah, that's a good place, if the herbs can be kept shaded. Maybe if you covered your herb bunches with a brown paper bag, you'd have better results. The bag should be punched with several holes to allow for air circulation, and it will keep the herbs out of light, and free from dust or bugs, and will collect any falling bits.