OK, they've admitted to throwing acid, but what we are talking about is butyric acid. It smells nasty, but it's not going to do any real harm.
So, when you hear about Sea Shepherd throwing "chemicals" and the like. We're talking about this:
Butyric acid, (from Greek βουτυρος = butter) IUPAC name n-Butanoic acid, or normal butyric acid, is a carboxylic acid with structural formula CH3CH2CH2-COOH. It is found in rancid butter, parmesan cheese, and vomit, and has an unpleasant odor and acrid taste, with a sweetish aftertaste (similar to ether). Butyric acid can be detected by mammals with good scent detection abilities (e.g., dogs) at 10 ppb, whereas humans can detect it in concentrations above 10 ppm.
Butyric acid is a fatty acid occurring in the form of esters in animal fats and plant oils. The glyceride of butyric acid makes up 3% to 4% of butter. When butter goes rancid, butyric acid is liberated from the glyceride by hydrolysis leading to the unpleasant odor. It is an important member of the fatty acid sub-group called short chain fatty acids. Butyric acid is a weak acid with a pKa of 4.82, similar to acetic acid which has pKa 4.76. The similar strength of these acids results from their common -CH2COOH terminal structure. Butyric acid has density 0.96 g/cm3 and molecular mass 88.1051; thus pure butyric acid is 10.9 molar.
Boo frickin' hoo. What they have to suffer for their research.