The term 'safelight' is pretty confusing to beging with, because none of them are safe. All they do is protect the paper for a certain time. If that time is just a few minutes, they are not safe, if it is 1/2 hour, they are, because you often need a combined processing time of 15-30 minutes.
The Wratten 1A filter is is OK if you don't have papers that are sensitive above 600 nm, because that's where Wratten 1A stops. Wratten 2 is better, because it goes to 640 nm. By the way, the Wratten OC (light amber) has a 10% transmittance above 560 nm, which can harm some papers. If you don't know your paper's spectral sensitivity, do yourself the favor and test your safelight.
In the dark, expose, but don't process, your paper under the enlarger so that it would develop to a light gray. Then, drop six coins on it and expose it to the safelight. Take one coin off after 1, 2, 4, 8, 16 and 32 minutes. Then process the paper normally (preferably in the dark or at least away and shielded from the safelight). How many tell-tale signs can you see? You should not see anything but the 32-minute 'coin' to be 'safe'.
Many people do this test, and only then realize, why they never printed an image with brilliant highlights and good midtone contrast.
Don't forget, you can make your safelights 'safer' but not only changing filters. A dimmer bulb will also extend the 'safe' time.