blue tarp safe to use?

I'm setting up my grow room and I need to block an attic door (I had to remove the door so I could put ducts coming off my 600w HPS so I wouldn't have to cut a hole in the door)

so I used a typical blue tarp to block the door off, but when I opened the tarp it said if it is exposed to an open flame it will catch on fire...

if I have a 600w with cool tube should I be worried that it can catch fire from the light?

I think the tarp will be about 1 and a half feet away...

it just sucks because I've already bought this tarp and tacked it on and put a zipper on it...

will it be safe?

thanks

Johnny

I've decided to not take a chance and take it down... Gonna look for some flame retardant tarp