Thread: How much residual Methyl Bromide is potentially in MB treated pine pallets?

I was under the impression is was zero.

Any treatment is to treat any beasties in the wood at the time, not to provide protection afterwards.

I saw a paper once that discussed this very thing. Let me find it.

edit - well, that took me less than 4 minutes to find! Google was watching..... http://npic.orst.edu/factsheets/MBgen.pdf

Apparently, the half life of the treatment is 30 minutes....

Agreed. We used it to clean out the entomology labs ( orchard and vineyard pests). The virtue was a short half life.
Chase everybody home 3 PM Friday and gas the place. Open the doors 5 AM on Monday morning = done deal.

Back when heat treated pallets were difficult to obtain, all the wooden pallets of glass bottles and other components for the pharmaceutical and food industries were treated with methyl bromide prior to their release from customs.

As already stated, the residual toxin is zero.

mick

So why all the fuss about MB treated pallets and the description - DO NOT USE?

I think there is something in that, and that is some countries seem to use MB to treat pallets (as cheaper) and when it comes to cheap, cheap is nasty, nasty is dangerous. Where as Japan, Europe and the UK for example use HT.

Me personally, I wouldn't use them for anything other than keeping stuff off the floor in a flood, but then again, if i saw the MB sign i wouldn't touch it to begin with.

But each to their own i guess.

The pallet I picked up was stamped AU for origin. At 5m long I suspect it was used for shipping locally manufactured pvc electrical conduit.

After some initial hesitation I ran the rough sawn stuff through the thicknesser so it is smooth enough to use as shelving. I took the usual precautions and didn't notice any skin irritation or breathing difficulties after completing the limited amount of processing it required. So the dire warnings about how using it will affect you seem to be alarmist.

From my further reading it appears the real reason to discourage use of MB treated pallets is due to the effect it has as an ozone layer destructor and managing things that can be affecting climate change. I wouldn't want to handle MB directly myself but recycling existing pallets as shelving to keep seldom used stuff off the ground in the garage seems better than letting it all go to landfill.

Originally Posted by Fuzzie

So the dire warnings about how using it will affect you seem to be alarmist.

Not so!

The main risk is skin absorption &/or inhalation of residual MB that may still be present on the pallets or dunnage, trapped in pockets in the wood or absorbed by "fatty oil" contaminants on the pallet. I would suggest that knots in pine "probably" absorb & retain MB.

MB is readily absorbed by inhalation / skin exposure and has a 12-14 day "half life" in the human body, so slow to disperse / expel. It has rather nasty neurotoxic effects that have a delayed onset so it is particularly difficult to notice any exposure at the actual time of exposure. This is why "chloropicrin (2%) is often added as a sensory warning agent."

It is important to note that "bromide" (as bromopheniramine maleate or hyoscine hydrobromide) is contained in many pharmaceuticals used to control "flu" symptoms and travel sickness that carry warnings about avoiding excessive / prolonged use because of potential neurotoxic symptoms / effects.

MB exposures occur from,

• poor venting procedures
• goods in the container have an absorbent quality e.g. wood, nuts and seeds
• off-gassing from items in the container, or
• entrapment of the gas in packaging
• Methyl bromide can diffuse through plastic
• unknown provenance (history) of the item i.e. pallet / dunnage.

"Methyl bromide is a neurotoxic gas which can affect the central nervous system. It is suspected of causing genetic defects."

"Methyl bromide gas is able to penetrate many substances such as concrete, leather and rubber."

"It is lipid soluble and able to penetrate the blood brain barrier with effects on the central nervous system."

"Workers may not realise they have been exposed to methyl bromide because it has no odour and the onset of symptoms is delayed. "

"Depending on exposure levels it can cause headaches, dizziness, vomiting, nausea, tremors, slurred speech and irritation to the eyes, respiratory system and skin. Exposure to high concentrations may cause pulmonary oedema (fluid in the lungs) or death."

"The main routes of absorption are through inhalation and the skin. "


"Absorption by skin may readily exceed vapour inhalation exposure."

"It is excreted by exhalation and in the urine. The half-life of inorganic bromide is about 12 to 14 days."


"The most important systemic effects are neurological: headache, dizziness, vertigo, slurred speech, nausea and vomiting, confusion, blurred vision, twitching and possibly
convulsions and coma. Onset may be delayed from 30 minutes up to 2 days post exposure. Ingestion is unlikely but methyl bromide is extremely poisonous if ingested."

"In March 2002, two South Australian carpenters employed by a stevedoring company were directed to retrieve timber that had been fumigated with methyl bromide 10 hours earlier. When cutting the timber inside a ship, they developed headaches, nausea, numbness and profuse sweating and were hospitalised for four days."

The carpenters would have been exposed to residual MB in the timber and also to residual MB gas not properly vented away. MB is heavier than air so would easily accumulate in the hold of a ship.

Quotes are from,

Methyl bromide health monitoring guidelines (worksafe.qld.gov.au)
Technical Information - Methyl Bromide (fumigationservice.com)

Even if you are confident that the MB treated item/s may not contain any residual MB -- why take the risk?

ps. any wood worker who has used "imported" timbers has probably worked with timber that was treated with MB. There is no requirement to declare if the "product" was treated with MB.

Mick, I have no doubt Methyl Bromide is bad for humans, just as there is no doubt it is also bad for the ozone layer. My question was how much residual MB is likely to exist in a used pallet that has been out in the weather for some time to be reused in a non habitable ventilated area. It is hardly analogous to retrieving timber from a confined space a few hours after treatment.

Are you implying we should we not even use any imported timber or in fact anything packaged overseas?

Originally Posted by Fuzzie

Mick, ???

Are you implying we should we not even use any imported timber or in fact anything packaged overseas?

No, I'm not. The issue is "you don't really know" how long ago a stick of timber has been treated by MB. In the scenario you mention (imported timber & pallets etc) it would be "generally recognized as safe" (GRAS) as per the recommended procedures for MB treatment. Florists are probably more at risk from MB than wood workers due to the perishable nature of their product and the potential for residual MB.

The point I was making is that we are using timber that has or may have been treated with MB without realizing it or being informed that it may have been.

What I am saying is it is your informed choice to use it with caution but please do not propagate a falsehood "So the dire warnings about how using it will affect you seem to be alarmist."

The delayed, sometimes years, neuro-toxic and cancer linked symptoms are slowly being unraveled by oncologists who are investigating the increasing incidence of cancers.

I think the short answer to your question is: "If you feel uncomfortable using it, don't". However, the likely dosage rate from any entrapped CH3Br is highly likely to be minimal, if not negligible.

It's an interesting topic because it set me wondering how the vast quantities of imported timber are, or were in the past, treated by AQIS. Kiln drying would easily qualify as heat treatment but from memory there's an expiry date on its certification.

mick

OK, the trouble with "Half Life" calculations is similar to the problem with the snail crawling to the edge of a cliff. The snail starts 2 feet from the edge of the cliff and crawls half the distance to the cliff every day. How many days does it take before the snail plunges off the cliff? The answer is that it never happens because there is always half the distance left. Not realistic but the numbers bear it out.

With the MB half life of 30 minutes, the residual MB after one day or 48 divisions by 2, the amount remaining borders on being undetectable. After just 4 hours there is 0.39% of the original left in the pallet. If a kilogram of MB was retained within the pallet (unlikely) after treatment, less than 4 grams would remain. After 8 hours the pallet would have retained 0.156 grams from the initial unlikely kilogram of MB.

If the pallet still remains in the discard pile when reading this, the only way that one could know that the pallet was treated with MB is that the pallet was branded with the letters MB.

Originally Posted by rrich

OK, the trouble with "Half Life" calculations is similar to the problem with the snail crawling to the edge of a cliff. The snail starts 2 feet from the edge of the cliff and crawls half the distance to the cliff every day. How many days does it take before the snail plunges off the cliff? The answer is that it never happens because there is always half the distance left. Not realistic but the numbers bear it out.

This is part of Zeno's Paradoxes --> Zeno's paradoxes - Wikipedia

The answer, for those interested in such things, is Quantum Mechanics. It is also solvable with Calculus.

Poor snail. Never gets to the edge

Originally Posted by rrich

With the MB half life of 30 minutes, the residual MB after one day or 48 divisions by 2, the amount remaining borders on being undetectable. After just 4 hours there is 0.39% of the original left in the pallet. If a kilogram of MB was retained within the pallet (unlikely) after treatment, less than 4 grams would remain. After 8 hours the pallet would have retained 0.156 grams from the initial unlikely kilogram of MB.

If the pallet still remains in the discard pile when reading this, the only way that one could know that the pallet was treated with MB is that the pallet was branded with the letters MB.

Yep. 100% agreed.

I really don't get what all the hyperventilating is about here.

Half-lives are easy to understand. If something was ASTOUNDINGLY RADIOACTIVE 6 months ago, but with a half life of 30 minutes, its residual radioactivity would be essentially zero.... less than that from a piece of granite.


The whole BuT yOu JuSt DoNt KnOw is nothing but F.U.D.


Use the pallet.

Now, the REAL question, is should I use these to make childrens toys

Originally Posted by woodPixel

Now, the REAL question, is should I use these to make children's toys

I don't see why not. Even if there was some residual MB deep inside the timber, the machining process and just sitting around your shed, it would dissipate.

Originally Posted by woodPixel

Now, the REAL question, is should I use these to make childrens toys

Not sure, lets let the stigma of chemicals call the shots. Why don't we do a " MB scrap wood challenge", we'll all make some toys, label them "made from pallets treated with Methyl Bromide" and see many get sold.

Answer - ZERO.

The question was put out there concerning the level of toxicity to find out if they should use them?, i say no, some say yes, but think about it logically, if you wouldn't make kids toys out of it then theoretically speaking it shouldn't be used, but again, each to their own.

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