Here's an interesting posting I found that lists helpful and harmful ingredients.

10 INGREDIENTS TO AVOID PUTTING ON YOUR HAIR!.
Most of the commercially available hair care products today use harmful, potentially carcinogenic ingredients.
1. ISOPROPYL ALCOHOL: This is a solvent and denaturant (poisonous substance that changes another substances natural qualities). Isopropyl alcohol is found in hair color rinses, body rubs, hand lotions, after-shave lotions, fragrances and many other cosmetics. This petroleum-derived substance is also used in antifreeze and as a solvent in shellac. Hair reacts very badly to isoalcohol and this ingredient should be avoided at ALL costs. It will dry your hair out and break it off. According to A Consumer's Dictionary of Cosmetic Ingredients, inhalation or ingestion of the vapor may cause headaches, flushing, dizziness, mental depression, nausea, vomiting, narcosis and even coma.
2. MINERAL OIL & PETROLATUM: The best baby oil is made from almonds. But the oil which being sold as baby oil is 100% mineral oil. Mineral oil is a derivative of crude oil (petroleum) that is used industrially as a cutting fluid and lubricating oil. This commonly used petroleum ingredient coats the skin and hair just like plastic wrap. The skin's natural barrier is disrupted as this plastic coating inhibits its ability to breathe and absorb the Natural Moisture Factor (moisture and nutrition). The skin's ability to release toxins and wastes is impossible through this "plastic wrap," which can promote acne and other disorders. It further hinders normal skin respiration/transpiration by keeping oxygen out. This process slows down skin function and normal cell development causing the skin to prematurely age. Holding in large a mounts of moisture in the skin can "flood" the biology and may result in immature, unhealthy, sensitive skin that dries out easily. Petrolatum - A petroleum-based grease that is used industrially as a grease component. Petrolatum exhibits many of the same potentially harmful properties as mineral oil.
Honestly, this stuff belongs in your engine, not on your hair. Regardless of "Well, my Grandma used vaseline on her hair and it grew ", the bottom line is this stuff is bad. It was bad for Grandma and it is bad for you. Period.
3. PEG: This is an abbreviation for polyethylene glycol that is used in making cleansers to dissolve oil and grease as well as thicken products. Because of their effectiveness, PEG's are often used in caustic spray on oven cleaners and yet are found in many personal care products. PEG's contribute to stripping the Natural Moisture Factor, leaving the immune system vulnerable. They are also potentially carcinogenic.
4. PROPYLENE GLYCOL (PG): As a "surfactant" or wetting agent and solvent, this ingredient is actually the active component in antifreeze. There is no difference between the PG used in industry and the PG used in personal care products. It is used in industry to break down protein and cellular structure (what the skin is made of) yet is found in most forms of make-up, hair products, lotions, after-shave, deodorants, mouthwashes and toothpaste. It is also used in food processing. Because of its ability to quickly penetrate the skin, the EPA requires workers to wear protective gloves, clothing and goggles when working with this toxic substance. The Material Safety Data Sheets warn against skin contact, as PG has systemic consequences such as brain, liver and kidney abnormalities. Consumers are not protected nor is there a warning label on products such as stick deodorants, where the concentration is greater than that in most industrial applications.
5. SODIUM LAURYL SUFATE (SLS) & SODIUM LAURETH SULFATE (SLES): SLS is used in testing labs as the standard ingredient to irritate skin. Used as detergents and surfactants, these closely related compounds are found in car wash soaps, garage floor cleaners and engine degreasers. Yet both SLS and SLES are used more widely as one of the major ingredients in cosmetics, toothpaste, hair conditioner and about 90% of all shampoos and products that foam. They are used in personal-care products because they are cheap. A small amount generates a large amount of foam, and when salt is added it thicken to give the illusion of being thick and concentrated. (SOME OF THE NITROSATING AGENTS ARE: SLS, SLES, DEA, TEA, MEA). Shampooing the hair with a product contaminated with these substances can lead to its absorption into the body at levels much higher than eating nitrite-contaminated foods.
Mark Fearer in an article, Dangerous Beauty, says, "...in tests, animals that were exposed to SLS experienced eye damage, along with depression, labored breathing, diarrhea, severe skin irritation and corrosion and death." According to the American College of Toxicology states both SLS and SLES can cause malformation in children's eyes. Other research has indicated SLS may be damaging to the immune system, especially within the skin. Skin layers may separate and inflame due to its protein denaturing properties. It is possibly the most dangerous of ad ingredients in personal care products. Research has shown that SLS when combined with other chemicals can be transformed into nitrosamines, a potent class of carcinogens, which causes the body to absorb nitrates at higher levels than eating nitrate contaminated food." According to the American College of Toxicity report, "SLS stays in the body for up to five days..."

Ascorbic acid is the same as Vitamine C. It neutralizes any chloride in the water.

Yes, I think VO5 Products are Safe to use on the hair.  Even today's products.  I can use anything from Alberto VO5.  I love them all!!!  I use the extra body shampoo and conditioner, the hot oil treatments, and hair dressing oil.