No purge BHO and cooking oil spray

If butane is in lighters(we inhale) and is in cooking spray(Pam) why do people make such a big deal on purge?

Please exclude answers about taste/quality as you are no doubt right. My question pertains to health risks.

Go huff on a Bic lighter for 5 mins then "try" and type in your response. Actually better dial 911 before hand and have them.on stand-by. Your gonna need it.