Softwood lumber is cellulose and hemicellulose which are polymers of glucose. It should not be any more dangerous than paper assuming it is well seasoned and dry without sap or mold (fungi). Preservative treated materials and anything containing asphalt, abrasives or solvents are pretty easy to spot and avoid. But I suppose kids can be allergic to anything.

Thanks Dame and JDS! Sis-in-law's reaction scared me a bit that I had just poisoned my children. :)

Dame, I agree, a box of nails may not be "safe" but it sure kept them occupied! They looooved hammering nails into the wood, and we didn't have one injury! Successful day, I say. (Of course I didn't mention the nails to SIL, she may have fainted)

We used to have a Thanksgiving-time party in my barn where we got together with a bunch of guys and turned 2x4s and x6s into blocks, sanded them, and then packaged them for local charities and orgs to give out at Xmas along with clothing, food, etc.

As pointed out, as long as it's just non-PT lumber scraps, I don't see a problem.

Honestly, Fam, I'm more concerned about your sister-in-law's lack of boundaries. :-( I don't agree with the way my brother and his wife are raising their kids, but I keep my mouth shut because no one's life is in danger. Live and let live.

By your username, I assume you have 4 kiddos? If so, I'm guessing you probably have a little more experience than your sis-in-law in the parenting department (and even if you don't, they're still your kids and the only other person who gets a say is your husband, lol), so chin up! You and your husband are the experts of your own little family. :-)

Oooo, Ichabod, what a great idea! I think you just helped me make our Thanksgiving plans!

Yes, Dame, SIL definitely has some boundary issues. But I know that she's coming from a place of love, and I've never doubted that. Also having a few states worth of a buffer zone helps immensely; there's no daily interference with our lives. She is a science teacher and a new age hippie, and I was a social worker/family consultant in my former life before having kids of my own. I go to her if I have questions about anything to do with homeopathic medicine, better food choices, etc., and she comes to me for parenting guidance. We both know that it's only advice and to apply as we wish to our own families. This particular instance was just casual chit-chat that led to such a strong reaction that it shocked me and scared me a bit. :)

When I was in the fifth grade, I remember making a throwing spear from a scrap 2x4 I found. That was when kids regularly brought their jackknives to school and practiced throwing them at things in the grass. Nowadays, I'd be off to juvie and my parents to the hoosesgow.

Maybe she's not familiar with construction and thinks they're using pressure treated wood for framing? (It's the only reasonable thing I can come up with....) Tell her you're actually being green, and making toys out of stuff that would be destined for a landfill. :)

I grew up playing with all sorts of construction scraps, never did me any harm apart from a splinter or two. We used drywall scraps as chalk for sidewalk drawing, we made tree houses and weapons from bits of wood, bent nails, and tarps. We even "liberated" a few materials from various jobsites... good times. ;)

Anyway. Plain pine or fir should be fine. Some people are allergic to cedar, but if so, you'll find that out right away. If the plywood has formaldehyde, that's not good, but it won't kill them, either. Just keep them from eating anything, or beaning each other with hammers.

Just keep them from eating anything, or beaning each other with hammers.

Some people are just no fun. ;-)

I grew up playing with all sorts of construction scraps, never did me any harm apart from a splinter or two.

that you KNOW of.... ;-)

Perfect justification for the demise of CCA treated lumber(Copper/Chromium/Arsenic) and the rise of ACQ.

Alkaline Copper Quaternary (also known as ACQ) is a water based wood preservative method recently introduced in countries where there is a demand for alternatives to Chromated copper arsenate (CCA).[1] The treatment is made up of copper, a bactericide and fungicide which makes the wood resistant to biological attack, and a quaternary ammonium
compound (quat) which acts as biocide, increasing the tolerance of
treated timber to copper-resistant bacteria and fungi, and also acting
as an insecticide.

Psst---do NOT tell your SIL about either types of wood preservative---she seems to have enough monsters to suffice.

My point is framing wood that is plain wood is no different than the wood in childrens' toys. Or wooden kitchen spoons. Or kitchen cabinets.

Just dispose of the colored(green/yellow.blue/pink) wood since those are treated with chemicals. Oh, don't burn those either.

Somewhat like Jannicone, my parents did a major remodel/addition when I was about 8 and we lived in the house during the remodel (the two front bedrooms were untouched and they left the old kitchen in until the new one was finished. I was old enough to use a hammer and nails and, oh, what fun I had building all sorts of things. -- tables, chairs, boxes. The finish carpenter was wonderful -- he taught me how to hammer a nail straight and every now and then would cut a scap to the size I needed. Of course these were the dark ages, but it left me fascinated with building.

My dad and granddad were both contractors and oh the wonderful things they made for us out of leftovers. I loved playing teacher with my dolls and they made me a schoolhouse complete with desks and "chalkboards." And my brother had an awesome fort. I never would have thought twice about letting my own kids play with all the leftovers if SIL didn't have such a strong response to it. I just needed to double-check with you kind folks that I didn't miss some huge news public announcement that framing lumber is causing kids to grow extra eyeballs and limbs. :)

The denser the wood the easier it is to build structures. My son took 40 lbs of hardwood blocks back on the plane after a recent visit. I love the sound on FaceTime when a tower falls down and my grandson says "all fall down".

"Treated" lumber is easy to spot: It has a greenish tint. it's distinctly heavier than a piece of untreated the same size.

And, because it also distinctly more expensive, it is only used where the rot-resistance is needed. It will not be used for the interior wall framing or the roof framing.

Offcuts from the framers will be normal wood colored and look like the whitewood studs at any lumber yard. Fabulous play material!

what about all those play forts with the slides and swing sets, in every
other backyard? Aren't those made out of pressure treated lumber?

Millions of dollars of CCA-treated playground features have been demolished in the US and Canada to be replaced by ACQ-treated wood, plastic or bare fields. Even if some scientists have pointed to easier alternatives. Oh, like handwashing after playing.

Pressure treated wood is now more light brown than green.

Okay, so in light of the photo above, how do you visually tell the difference between that and the regular stuff? Especially random scraps that don't necessarily have labels/stamps/imprints? Or does it not matter, because that kind of (presumably new) pressure treated is okay...?

Problem solved:

A short lesson on construction lumber. Lumber is cut from trees at a sawmill, stacked(with spaces between boards) and either air dried(6+ months or more) or kiln dried(in a huge heated oven for several hours) to remove most of the moisture in the wood. That stabilizes the wood so it does not warp as it dries.

Untreated construction lumber is the same color all the way through a piece where a cross section is visible.

Treatment is done to better protect the wood from moisture damage, insect infestation, or mold formation. The treatment consists of stacking the lumber on rail cars(usually specially built) and placing the rail cars in huge pressure chambers where the treatment liquid is introduced and the chamber pressurized to force the liquid into the wood fibers.

Then the treated lumber is again dried to reduce the moisture from the treatment liquid. Often, due to demand, this second drying is shorter(and sometimes eliminated) in order to ship. That is why some treated lumber is heavier than standard. Properly dried treated lumber is virtually the same weight as untreated lumber. I've picked up treated boards that were dripping liquid. As long as I did not get that liquid in my mouth, on my face, or in my eyes, there were no bad effects---but I did wash. I also never used treated lumber that was that wet, since the probability of it warping was high.

Treated lumber is generally only used where framing contacts concrete, dirt, or in wet areas.

Treated lumber generally shows a different color in the center of a cross cut section. Newer treatment colors are yellow and light green. The previous treatments were copper, chromium, and arsenic(CCA) compounds. Those chemicals protected from moisture(the CC's) and insect(the A) infestation.

Newer treatments are chemicals that offer similar protection without arsenic. (ACQ--Alkaline copper quaternary)

There are external treatments that coat lumber in blue or pink colors, which are obvious. That coating is anti fungicide or fire retardant treatments.Those can be used as wall studs or ceiling/floor joists. Probably not a good idea to let kids play with scraps of those.

So, standard, untreated construction lumber is simply trees made into boards and completely harmless(unless an allergy is present).

Treated lumber is treated with chemicals and usually fairly recognizable. Best to dispose properly(DO NOT BURN!) and keep away from kids.

I remember my mother giving us a large stump and a bag of nails as a toy. I also remember her giving us an old engine to take apart, so -- no -- I have no problem with these playthings.

My own kids have been allowed to take apart all sorts of broken things: Toaster ovens, old ipods, etc. Sometimes we bought old junky stuff at Goodwill specifically for them to take apart. Incidentally, my kids turned out smart. Very, very smart.