Participation is open to all persons who are directly and materially affected by the STP topic. If someone is interested in joining an STP they should contact the Project Manager identified on the STP Chart page and to apply, complete the online STP Application.) All STP members must have a completed application on file that lists their interest category and technical qualifications. Even though the membership in an STP is open, membership may be restricted due to balance constraints. An STP Chair has the final decision on the minimum or maximum size for an STP.

STP membership is limited to only one voting member per organization. It is the responsibility of the member organization to coordinate its vote.

Individual participants interest category shall be determined by the STP Chair during the application process.

Independent consultants and experts are usually classified as a General Interest participant. On occasion, however, independent consultants in this category may be retained by a client to advocate on behalf of the client with regard to a specific issue or issues before the STP. As to these specific issues, the independent consultant should not be regarded as a General Interest participant because to do so could result in a balance of interests that was not intended. Therefore, the STP member shall refrain from voting on any proposal, comment or other matter relating to those issues to which they are being retained.

No individual shall represent more than one interest group. There shall be no proxy voting.