In this blog, Dr. Jennifer Lares, Ben Schmidt and Larry Stuart Jr. Discuss:
· What not to cremate: Items like pets, trash, synthetic materials, and previously cremated remains should never go in the cremation chamber.
· Environmental and safety tips: Improper materials can harm equipment, release toxins, and impact the environment—and what to use instead.
· Thoughtful cremation practices: Respectful and practical solutions for honoring the deceased while maintaining safe and efficient cremation processes.
When it comes to cremation, it might surprise you as to what shouldn’t go into the primary chamber. In this post, we’re joined by three Raven Plume contributors; Dr. Jennifer Lares and Ben Schmidt, two licensed funeral directors and mortuary science professors, along with Larry Stuart Jr., an internationally renowned cremation expert. Together, they’ll share essential guidance on what items should stay out of the cremation chamber—and why these choices matter for safety, respect, and the environment.
Previously Cremated Remains
This is not an uncommon request from families!
Now, we all know that cremating two people together is a definite no-no, right? But let’s consider a situation where someone suggests including an intact body with someone who’s already been cremated. What would you say to that?
First off, it’s a legal and ethical issue. Legally speaking, only one person is allowed to be cremated at a time, period. Even if one of them is already cremated. So, unless there's a specific judge’s order, it’s not only inappropriate but likely illegal.
Exactly. And from a practical standpoint, it doesn’t make much sense either. The previously cremated remains are already processed—there’s no reason to place them with the body in the retort.
If families want the remains intermingled, they can absolutely do that after the new cremation, outside of the chamber. With the right paperwork and permission, it’s completely allowed and actually quite common.
Even Cremated Pets?
Some families want their pet’s remains cremated with them, but we know pets can’t legally be placed in a human retort.
‘Sneaking’ a pet into the chamber with a human body isn’t just against regulations; it’s simply not allowed .By law, pets must be cremated in a pet crematory, not in a human one.
If a family wants to have their pet’s ashes intermingled with their loved one’s, they absolutely can—after both cremations are complete. Once the pet has been cremated at a pet facility, the remains can be combined with the person’s cremated remains with the proper permissions in place.
I get that some folks (me included) treat their pets like family and would do just about anything for them, but I never understood the act of euthanizing a healthy pet after their pet parent dies, never mind including the pet into the container for cremation of their owner.
Is it safe to cremate trash?
What about the issue of come crematories reportedly using their crematory to "take out the trash." Larry, what's your take on that?
It’s a serious concern. It may seem like a good idea, but it isn't. Cremation units are specifically designed for Type 4 waste, which is essentially organic matter—like deceased humans and pets. These units are not built to handle solid waste like trash. Humans and pets are mostly water, so the cremation process works because of the way these units are designed. But trash is am entirely different thing. Trash falls under solid waste, which will release harmful emissions and pollution if it’s not burned in an incinerator that is designed to combust solid waste. That’s a major issue. Not only is it dangerous, but it’s also likely to produce visible smoke and pollutants that are harmful to the environment.
It’s not just a matter of what’s legal, but also about respecting the equipment and keeping the process safe for everyone involved. Plus, would you want your grandmother cremated in a trash incinerator!
Retiring American Flags by Cremation
As Navy veterans, Jennifer and I both know how important the proper retirement of the American flag is. But we’ve seen a trend where some places may cremate flags en masse, which seems like a valiant way to end them, but there are real issues with that approach.
Cremating flags in bulk, especially when they’re made of synthetic fibers, can cause visible emissions and pollution. The synthetic materials don’t break down the way natural fabrics do, and that’s a serious environmental concern.
I get that it's a respectful way to handle flags that are no longer fit for display, but you’ve got to think about the consequences. When you throw a bunch of flags into a cremation unit, you’re asking for pollution. The right way to handle this? If you’ve got a bunch of flags to retire, like from a Boy Scout group after Memorial Day, save them. Instead of cremating them all at once, you can place one unfolded flag on top of the container of. a veteran to be cremated.
Exactly. One flag won’t cause any issues, but a whole stack will definitely lead to visible emissions and pollute the environment. This way, you honor the flag while protecting the cremation process.
And it’s a simple solution that balances respect with environmental responsibility. Properly handling flags is nearly as important as properly handling the deceased.
Beware of Chlorinated Plastics
Cremating synthetic materials,, especially those made from chlorinated plastics, can cause some serious issues that we really need to be aware of.
Common sources of these materials include things like PVC plastics, some synthetic fabrics, and certain types of vinyl. In fact, many toys—like plastic action figures, dolls, and inflatable toys—are made from PVC, which, when cremated, releases hydrogen chloride gas. This can be an issue when thinking about long bone procurement; some agencies replace the bone with PVC pipes. If you find yourself in this situation, wooden prosthetics are an appropriate replacement. If you know your procurement agency does this, it is the responsibility of the embalmer to remove them before cremation.
Exactly, when the chlorine from the plastic vaporizes it will combine with the hydrogen atoms from the fuel and the air, it will create that poisonous gas. Funeral directors should advise families not to cremate items with the person that are made of these materials, even if they represent something important to them. A memorial set up including those items would be more important. The density and components of mortuary pouches are also perpetrators, not all mortuary pouches are designed to be cremated! Operators need to make sure that the person is in an appropriate alternative container and if there are these items found in the container during the last visual inspection they are removed before placing them in the primary chamber.
If the plastic melts instead of vaporizing, it can stick to the floor of the cremation unit or, worse, to the cremated remains. Once that plastic adheres, it’s a huge problem.
It’s very difficult to remove it without damaging the cremation equipment. If you try to scrape it off, you risk ripping out part of the floor, which is a disaster. And if plastic gets mixed in with the cremated remains, you can’t just throw part of the remains away before processing.
The plastic ends up contaminating the remains. It's not only disrespectful, but it also makes the process more complicated and less efficient. not to mention there are legal and ethical consequences of putting someone's cremated remains in the trash because you couldn't get the sparkly plastic goop out.
What about cold hard cash?
There was a crematory, many years ago, that was contacted by the U.S. Mint to cremate a couple of pallets of disused $100 bills. The owner/operator called up my Dad to ask them if this was okay. Dad, of course said, "NO! The unit is only designed to cremate deceased people and their containers." The customer replied with "Well...no wonder it smoked the entire time!" Not only is paper not to be cremated, those bills weren’t just paper—they had who knows what chemicals in the ink or the material. He was lucky the fire department didn't show up, or even worse, a news crew!
A great example of what we don’t want people to see coming out of a crematory, right? Doesn’t this make the opacity meter go crazy and freak the machine out? Are there environmental laws that might be violated here?
That's a great point, Ben. If the unit was equipped with an opacity monitor, it would be activated and the control system wouldn't be able to correct. The paper, in tight bundles like cash would be, would not have the same rate of combustion as Type 4 Waste. Different things burn at different rates and the cremation unit is only designed for deceased humans (or pets) so anything that would burn too slow or too fast would create havoc. This is why people with a higher percentage of body fat need to be handled differently than someone leaner. Body fat has a burn rate of 17X hotter and faster than muscle and organ tissue.
Embalming Chemical Bottles
You’d think it would be obvious, but I've heard fom operators often that they find empty embalming chemical bottles left in the cremation container. I think it's another way to dispose of something that should have gone in the trash. It is something that an operator can overlook when scrutinizing, when they're in a rush.
Right, and it’s a bigger problem than people think. Those bottles contain residue that, when burned, releases chemicals that aren’t exactly safe. There’s also no reason why they should be in there in the first place. Once the bottles are empty, they should be rinsed and placed in the trash.
Head and Limb Supports
And then there are the head blocks—another one operators occasionally forget. If they’re styrofoam, plastic or, even worse, rubber, burning them creates a whole new set of issues. The fumes are toxic, and the smell of burning rubber…well, it’s something you don’t forget!
Not to mention those rubber head blocks cost a pretty penny! It’s the kind of mistake you only want to make once, believe me. I remember the first time I smelled one burning; I knew right away what had happened, and trust me, you don’t want that odor lingering around.
Kitty Litter? Oil Dry?
I heard a few people have tried using kitty litter, oil dry, or other clay based materials instead of autopsy compound, thinking it’ll work just as well. But that stuff’s terrible for the crematory.
Yeah, I’ve seen it done, and quite frankly there’s also an ethical issue here considering there are more appropriate mortuary alternatives. Kitty litter might absorb fluids, but it’s not made to handle high heat, and it doesn’t belong on someone’s body cavities. It can end up hardening, intermixing with the cremated remains, and damaging the machinery.
People sometimes think they’re saving money but using the wrong materials just costs more in repairs and downtime as well as setting themselves up for a lawsuit.
Absolutely. The crematory equipment’s already under a lot of stress—adding kitty litter or oil dry just makes things worse. It’s one of those shortcuts that backfires every time.
Agreed. Stick with the right materials; it’s safer, and the crematory will thank you! If you have questions about the clay content of any of your autopsy compounds, ask your embalming chemical rep, but in general they are designed to be appropriate for cremation, and respectful to the deceased.
This is practical advice on what should never go into a cremation chamber, not only to maintain the integrity of your equipment but to remind you of best practice in funeral service. As you read, these choices aren’t just about rules—they’re about honoring the deceased and protecting the environment. The message is simple: small changes can have a big impact in ensuring cremation is handled with care and dignity.
