I have also been wary of insect sprays. Ads will have you think that you can just breathe it in like fresh oxygen and a sparkle shall appear in your eye, that may or may not have something to do with the chemicals you have just inhaled.
Rather than creating a toxic environment for workers, better ways to keep bugs out of the office are:
– install fly screens on doors and windows
– mix boric acid with flour to form little dough balls that will attract and knockout creepy crawlies
– citronella candles repel mosquitos
– essential oils of rosemary, lavender, spearmint, cedarwood among other repel bugs and flies
Then there is always the handy fly swat of course