The environment suit is a special medical radiation suit designed by Moira Brown to withstand the harsh environment of the Capital Wasteland. When equipped, its effects are an added 30 radiation resistance and 5 bonus medicine skill points (up to a maximum of 100). The environment suit may be repaired using radiation suits and advanced radiation suits, though only affecting the suit's low damage resistance of 6.
The environment suit may be obtained only by completing an optional objective during the Wasteland Survival Guide quest. While working on Chapter 2 of Moira's “Wasteland Survival Guide,” she will ask you to reduce your health below 50%, and extends the task to optionally come back with a crippled limb. After completing this task and its optional objective, you will receive the environment suit along with some Med-X.