On the toxic nature of butyric acid

Sea Shepherd threw glass bottles filled with butyric acid onto a Japanese whaling ship on the 15th of January. Paul Watson confirmed that the group launched butyric acid at the Yushin Maru No.2 as reported in The Australian.

Whale activists admit to stink bombs
By Melissa Jenkins | January 19, 2008

ANTI-whaling activists admit to throwing about 12 stink bombs onto a Japanese whaling ship after two of its crew were released, and are planning more attacks.

Two members of the Sea Shepherd Conservation Society, who were being detained on the whaling boat Yushin Maru No. 2, were yesterday handed to an Australian customs' vessel then returned to their ship, the Steve Irwin.

The Japanese Whaling Association (JWA) has accused the activists of throwing acid onto the sister vessel of the Yushin Maru No. 2 -- the Yushin Maru No. 3 -- overnight.

Captain of the Steve Irwin Paul Watson denied any attack on the Yushin Maru No. 3, saying he had not even seen such a boat.

But he confirmed the group launched a “retaliatory strike” of butyric acid “stink bombs” at the Yushin Maru No. 2, about one hour after activists Benjamin Potts and Giles Lane were transferred to the Australian customs boat, the Oceanic Viking.

Butyric acid is a non-corrosive substance and smells like rancid butter.

“We sprayed them with butyric acid, which is a noxious stink bomb, and the smell stays there for a few days. While it is on the deck it is pretty hard to do any work, like kill a whale,” Mr Watson said.

In the above report, the reporter Melissa Jenkins described that butyric acid is a non-corrosive substance and smells like rancid butter. According to her description, butyric acid is just a foul-smelling, non-corrosive substance that can hardly injure people, which echoes the view of Sea Shepherd. The following is a comment posted on www.news.com.au by a person who professed himself to be a strategist for Sea Shepherd.

As a strategist for Sea Shepherd I wish to bring to the public and media attention that the "ACID" used is an organic acid - Butyric Acid...a flavouring used in the Food Industry. It is more commonly known / identified as rancid butter...it is thrown on the flensing decks (not at people) where it permeates the timber. When whale meat is cut up on the deck it contaminates it rendering it unsaleable / useless. The other feature is that it stinks. Exageration and misrepresentation that it is "Acid" infers that it is akin to dangerous ionic acids such as Sulphuric or Hydrochloric acids which it is not. It is consumed daily by human beings and approved for food use & is biodegradeable. It is not in our charter to harm human beings or other creatures of the world we have a clean record on this account, IF the weak Gov't stood up to their election promise we would not be there.
Posted by: Tim Horwood of Belgrave 9:45am January 16, 2008
Comment 79 of 262

According to his description, butyric acid seems to be a harmless substance that is not so highly acidic as sulphuric or hydrochloric acids, consumed daily by human beings, and biodegradable.

These descriptions by Sea Shepherd and Australian media looks to be scientific. However, contradicting these notions, Japan Whaling Association claimed that two Japanese crew were injured when Sea Shepherd members threw the acid at Japanese sailors on Nisshin Maru last February.

Not only did Sea Shepherd deliberately ram the Kaiko Maru this year as well, they also threw acid at Japanese sailors and shattered glass bottles on the Nisshin Maru deck, resulting in injuries to two Japanese crew.

Other Japanese source says that butyric acid from a broken bottle splashed the face of one of the sailors. Fortunately, he did not injured heavily since he could soon washed the acid away. But his whole face was inflamed after the incident. He should have been blinded if he had not promptly closed his eyes when the acid splashed his face.

These comments from Japanese side sharply contradict the report and comment in the Australian media. Are the Japanese whalers deliberately exaggerating the fact?

When something is uncertain, bloggers usually search information on the Web. However, those who are working with chemical substances know that MSDS is the best source to consult first on the toxicity of chemical substances. MSDS (Material Safety Data Sheet) is a form cantaining basic data regarding the properties of a particular substance.

MSDS for butyric acid says the follwoings.

Harmful if swallowed or inhaled. Corrosive. Extremely unpleasant smell may cause nausea. Liquid may burn skin and eyes. Readily absorbed through the skin. Severe skin, eye and respiratory irritant.

Although the reporter of The Australian wrote "Butyric acid is a non-corrosive substance", MSDS tells us that it is "Corrosive".

Also, MSDS says that acute dermal toxicity (LD50) of butyric acid is 530mg/kg [rabbit], which roughly means you can kill a rabbit that weigh 1kg by administering 0.53 g of the substance onto the skin. By simple calculation, it is roughly estimated that a human who weigh 70 kg can be killed by administering about 37 g of butylic acid onto the skin. It is obvious that the amount of butyric acid thrown onto the Japanese ship is enough to kill more than several people.

MSDS says that butyric acid is readily absorbed through the skin and then degraded into other substances and that the biodegradation products are more toxic than butyric acid itself.

The high toxicity of butyric acid seems to be conferred by the toxicity of the biodegradation products rather than its acidity.

MSDS also tells us that CERCLA (the Comprehensive Environmental Response, Compensation, and Liability Act) in the US classifies butyric acid in "Hazardous substances".

During the piracy attack by Sea Shepherd, many of the bottles dropped on the sea failing to reach the ship. Those bottles will arrive at the seashore somewhere someday. If a child opened the bottle, what would happen?

The Australian government must know the toxic nature of butyric acid since MSDS is available to anyone. Purchase, storage and usage of harmful substances are usually regulated by law. The fact that Australian government has not detained the Sea Shepherd members might indicate that she is supporting Sea Shepherd to attempt murdering Japanese sailors and polluting environment, as Japan Whaling Association suggested. But I still hope the Australian government and media to cope rationally with this issue.

NOTE: MSDS is distributed in many places. I obtained one from www.sciencelab.com. Search "butyric acid" using the search box on the top page. You can find a link to the PDF file below "n-Butyric Acid, Reagent". Also, you can see a shortened version of the MSDS here.


Db said...

Check the MSDS for phosphoric acid. Sounds like pretty dangerous stuff! and yet, it's a common ingredient in soft drinks. Check the MSDS for acetic acid... even more scary! Yet, in its diluted state, it's common vinegar. Sodium flouride, that stuff you brush your teeth with, appears to be downright poison!
The point I'm making is that concentrated chemicals may appear to be extremely toxic, but may not be used in their concentrated form. Before we assume that one side or the other is lying, we'd need to confirm the concentration of the acid in question.

Aki said...

Yes, concentrated phosphoric acid is pretty dangerous. It burns skin. Even acetic acid can burn skin. A friend of mine once severely burned his sole with concentrated acetic acid.

As for the concentration of butyric acid that Sea Shepherd used, there is no publicly available data. However, according to The Australian,

“We sprayed them with butyric acid, which is a noxious stink bomb, and the smell stays there for a few days. While it is on the deck it is pretty hard to do any work, like kill a whale,” Mr Watson said.

In this comment, Paul Watson said “butyric acid, which is a noxious stink bomb”. When one says "butyric acid", it is usually pure butyric acid that is an organic liquid.

Since butyric acid is readily mixed with water, water is usually used when it is diluted. However, as seen in this photo, the liquid thrown at the whaling vessel looks to be an organic solvent. Undiluted butyric acid looks as an organic solvent.