The most common and most likely answer to this crossword clue is the 6 plus 2 plus 7 letter word TAKING NO CHANCES
I've seen this crossword clue in The Daily Telegraph
T
A
K
I
N
G
N
O
C
H
A
N
C
E
S
Buddy explains!
The straight part
We know that "Safety first presumably prevents one from seizing opportunities" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case safety first presumably prevents one from seizing opportunities = taking no chances.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.