I am going to nominate the film "The Alpha Incident," which was made in 1978.
The Alpha Incident is notable only for those who enjoy partaking in watching "B-movies." Having seen this movie myself, it is paced rather slowly and was made on what would generously be considered a "shoe-string" budget. Is it rather talky? Yup. Are there a lot of plot holes? Yup. Does the film suddenly end in a very unrewarding way? Yup.
And yet I can't fault this movie entirely. Its core premise (people quarantined in a confined area) predates other films such as "Quarantine" & "Rec." The film also tries to have a plot and plays it completely straight (unlike other films that winks and nods a bit too often at the audience).
Although the film would be far more likely to win a Razzie than an Oscar, I can't help but to add this film to the list.