Each word or phrase below is incomplete. The words that are missing have something in common.

1. STACK
2. MAKER
3. THE MAGIC ON
4. ZAN OF THE APES
5. PUSH THE PANIC ON
6. ED IN LIKE SARDINES
7. C ON THE BARRELHEAD

Answers:

The missing words are all related to smoking:

1. SMOKEstack
2. MATCHmaker
3. PUFF the magic DRAGon
4. TARzan of the apes
5. Push the panic BUTTon
6. PACKed in like sardines
7. cASH on the barrelhead 

Credit: LA Times Crossword
Sylvia Bursztyn and Barry Tunick
SMOKE-FREE ZONE  (adapted)