From the WD-40 web site they describe it as a petroleum based product. That doesn't imply that it does not contain fish oil but it is primarily petroleum based. As such it is polluting, but in the quantities used putting it on a lure it likely does not matter one bit. From the MSDS sheet (see further) fish oild might be part of the 10% that is not petroleum based.
The web site stated also that it was developed as a water displacement formula, the WD, and that this formula was the 40th attempt.
So is it the scent that attracts the fish or the sheen that it imparts to the water around the lure, or both?
Wd -40 attacks some plastics but not others. The trick is to know which is which. I remeber back in the days of the Rubics Cube craze people spraying WD-40 on it to make it easier to turn and the cube then falling apart. The WD-40 web site states that "Polycarbonate and clear polystyrene plastic are among the few surfaces on which to avoid using a petroleum-based product like WD-40." My problem is I don't recognize one plastic from another, so it is trial and error. Does Scotty use polycarbonate or polystyrene in the downriggers?
The following information I came across is interesting;
"Attract fish. When sprayed on fishing bait, WD-40 covers up the scent of human hands on the bait to better lure fish, according to USA Today. The WD-40 Company receives hundreds of letters from consumers confirming this use, but prefers not to promote WD-40 as a fishing lure since the petroleum-based product could potentially pollute rivers and streams, damaging the ecosystem."
The following comes from the MSDS that WD-40 provides for the product;
SECTION 3 COMPOSITION INFORMATION ON INGREDIENTS
Ingredient CAS Number Percent
Stoddard Solvent 8052-41-3 45-50%
Petroleum Base Oil 64742-65-0 30-35%
Non-Hazardous Ingredients Proprietary <10%
I had to look up Stoddart solvent, but it is also petroleum based. The following describes it;
" Stoddart Solvent (Casno: 8052-41-3) is used as a multipurpose
petroleum solvent; uses include paint vehicles; thinning agent for
paints, coatings, and waxes; printing inks, adhesives; solvent in
liquid photocopier toners; solvent in dry cleaning; degreaser for
engine parts in machine and auto repair shops.
Stoddard solvent (high flash, low aromatic grade), was nominated by the United Auto Workers as one of several organic solvents that are used with substantial exposure in transportation, equipment and related metal working industries. For most of these solvents, there was evidence for human health risks particularly occupational cancer and respiratory toxicity found in epidemiology studies, from cases reports, from acute and subacute testing in animals from inadequate chronic exposure studies. Stoddard solvent is a mixture of numerous
hydrocarbons derived by refining crude oil. The mixture consists of
three major groups of components: linear and branched alkanes (30-50), also known as paraffins; cycloalkanes (30-40); and
aromatic hydrocarbons (10-20). There are various types of Stoddard
solvent with different flash points and composition of linear alkanes, cycloalkanes, and aromatic hydrocarbons. ASTM specifies four types of mineral spirit (Stoddard solvent): Type I--Regular; Type II--High flash point; Type III--Odorless; and Type IV--Low Dry Point. "