Like in other wobs, there is a clear chronology on how to apply, when to answer, and what to do, if you do not get access. All articles reffered to below are in Regulation 1049/2001 on Access to Documents in EU institutions.
If you are looking for information on the environment, you should consider regulation 1367/06 on access to environmental information. It is broader, so also non EU-citizens can apply, and the obligation to weigh the public interest in transparency is stronger than in the general wob (article 6 in the regulation on access to the environment). However the practical procedure is like in the general regulation (article 3 in the regulation on access to the environment).

First application is sent to the institution.
Usually you receive a confirmation by the institution, but that is not obligatory.
Within 15 EU-working days you receive an answer by the institution. If you do not receive an answer, this must be considered as a refusal (article 7). NOTE 1: Sometimes the 15 days are counted from the day the institution registers your application, not the day it's sent. NOTE 2: EU-working days follow Belgian and other holidays and can differ from member states.

If your application was refused, you have now 15 working days to make a confirmatory application asking the institution to reconsider it’s position. (Article 8). Practice shows, that eventhough you address the same institution or department, the application is dealt with on a higher level of administration.
Within 15 EU-working days you will receive an answer by the institution. When the application concerns a long document or a large number of documents, it can prolong with another 15 days. If you do not receive an answer, this must be considered as a refusal (article 8).
 

If your application was refused at this level, you have the option within two months to ask the European Court of Justice to look at the case, or within two years to ask the European Ombudsman to do so (article 8.3).

Brigitte Alfter