Is it safe to remove one front chain ring?
You can remove the inner chainring without compromising the strength of the crank.
However, this will mean you will have to 'cross-chain' from the outer large ring to innermost largest rear sprockets to obtain lower gear ratios. Doing this accelerates wear on the chain, sprockets and chainrings.
Small chainrings and bolts are not expensive. Installing might require pulling the crank off the bike though.