So my research has actually found something useful now..
It seems
lead :yuck: is the industry standard stabilization agent for 'regular' PVC.
PVC degrades as a result of exposure to UV radiation, directly proportional to the surface area exposed.
As PVC breaks down it releases small amounts of hydrochloric acid which the lead absorbs.
A short time ago the risk of toxicity in PVC blinds was closely examined due to the large surface area exposed to sunlight. Electrical cords also present a risk. Some garden hoses are now labeled 'safe to drink from' if they do not contain lead. While a drink from the garden hose hasn't killed me, I wouldn't like to breath through the stuff too much.
Medical grade PVC
IS in fact different. Medical, or Grade-E PVC is manufactured using alternative stabilization agents and is totally lead free.
Contrary to my suspicion it's not just a marketing tool and
must be manufactured according to requirements and issued a SGS (a quality assurance organization) certificate.
So it seems the small additional investment is well,
well worth it!
Don't breath through industrial hoses!
It's rather concerning how hard some of this information was to find and the lack of warnings on products which we come in contact with daily. I'd much rather a 'not safe for breathing' label on an air hose than a 'hot' label on McDonalds coffee!
My research has come from a variety of online and printed sources. The most concise and a good summary is available at:
Lead and PVC The Reality-Based Community