I ran a search for Moraga's Heroes and Saints and Other Plays in Melvyl, and I found that I could request a copy of it from another UC library using my UCNetID.
One of the plays in Moraga's collection, "Heroes and Saints", is about a Mexican immigrant community that has been poisoned by pesticides and other toxins.
I'm interested in learning more about the history of environmental racism, so I also ran a search for "environmental racism" in Melvyl. I found Cole's and Foster's (2000) From the Ground Up: Environmental Racism and the Rise of Environmental Justice, which was published by New York University Press.