A module to track chemicals, compounds, or other reagents (generically speaking, "products") that are synthesized in a laboratory and then which may be used or sent to collaborating labs. Each use can be recorded as a transaction.
The Filter Default module allows you to assign a default input format for new nodes and comments for each role on your site. It adds a 'Defaults' tab to the Administer > Site configuration > Input formats page on which you can manage the assignments.
Drupal 6 users should take a look at Better Formats module, which covers more ground than Filter Default.
Note: This functionality will be built into Drupal 7, so Filter Default will not be maintained beyond Drupal 6.