Dermatitis from Cutting Fluid: What CNC Operators Should Ask Their Supervisor For

Itchy, red, cracked skin on the hands and forearms of someone who handles coolant all day is most often contact dermatitis, which OSHA calls the most commonly reported skin disease associated with metalworking fluids. The fixes are mostly in your employer's hands: keeping the fluid at the right concentration and free of tramp oil, providing chemical-resistant gloves where gloves are safe to wear, and decent washing facilities. Barrier and moisturizing creams help, but OSHA says they are supplements only. This article explains the guidance; it is not medical advice, a rash that persists needs a health professional.

Why coolant gets under your skin

OSHA's Metalworking Fluids best practices manual describes contact dermatitis as itchy skin and a rash, "often with cracks, redness, blisters, or raised bumps". There are two kinds. In irritant contact dermatitis, the rash stays where the skin touched the substance. In allergic contact dermatitis, it can spread beyond that area. Citing NIOSH, the manual says 14 to 67 percent of workers exposed to metalworking fluids are at risk of developing dermatitis, and that once the skin is compromised, very small exposures that did nothing before can set off another episode.

Fluid type matters. According to OSHA, people working with water-based, synthetic and semisynthetic fluids are most at risk of contact dermatitis, while straight oils are more often linked to acne-like problems, pimples, red bumps with yellow pustules on skin in contact with oil-soaked clothing. NIOSH 98-116 adds folliculitis and keratoses to the straight-oil list.

Why "toughing it out" is a bad idea

NIOSH 98-116 notes that many workers keep working with skin lesions and considerable burning and itching, and that some are eventually disabled by their skin disorders. It describes the prognosis for workers with metalworking fluid dermatitis as poor, which is why it puts the emphasis on prevention, limiting skin contact through engineering controls and protective equipment. NIOSH also recalls that in 1991 the industries with the highest incidence of skin disorders (including fabricated products, screw machine products and general industrial machinery) all involved potential metalworking fluid exposure. OSHA's manual adds that untreated dermatitis can lead to more serious complications, so early treatment matters.

The usual suspects on the shop floor

OSHA's manual lists the factors that can cause contact dermatitis in metalworking operations. Many of them are things an operator can spot and report:

• Clothing soaked with fluid, as the water evaporates from fabric, it leaves fluid behind at much higher concentration than intended.
• Not washing after contact, so fluid stays on the skin.
• Fluid mixed stronger than recommended, or high alkalinity in the in-use fluid, which strips natural skin oils.
• Tramp oils (hydraulic fluid, gear and spindle oil, way lube, grease). OSHA calls tramp oil "one of the main causes of dermatitis": these lubricants are not designed for repeated skin contact and carry metal fines that irritate the skin mechanically.
• Metal shavings in the fluid that abrade the skin; degreasers, cleaners and rust inhibitors.
• Washing with abrasive soaps, or water that is too hot or too cold; winter dryness.
• Prolonged contact, dipping unprotected hands and arms into the fluid again and again.

Gloves: not just any pair

OSHA's manual is direct: "Gloves and other protective equipment, where used to prevent dermatitis, must be chemical-resistant or impervious to the chemicals contacted." A cotton work glove that soaks up coolant can hold fluid against the skin all shift, the opposite of protection. NIOSH 98-116 likewise refers to clean, nonirritating and nonsensitizing gloves and aprons that shed, rather than react with, fluid ingredients.

There is a safety catch. Gloves can be a serious hazard around rotating tools and workpieces because of entanglement. The manual therefore says that if gloves are required, special attention should be given to guarding, and the employer should specify the operations for which gloves are permitted. The manual notes that water-repellent barrier creams are used primarily in machine shops where gloves cannot always be worn safely and water-based fluids are in use.

Under OSHA's personal protective equipment standard (29 CFR 1910.132), the employer must assess the workplace for hazards requiring PPE, provide the proper equipment and make sure it is used and maintained. Each employee who must wear PPE has to be trained, when it is needed, how to put it on and take it off, its limits, care and replacement, and must demonstrate that understanding before doing the work. Standards 1910.133 to 1910.138 expand on specific areas, including hand protection.

Creams and washing: helpful, with limits

• Barrier creams can protect against dermatitis if used consistently and reapplied through the shift. They should be applied only to healthy skin and not used if you already have dermatitis.
• Moisturizing creams replenish moisture and may also be protective.
• Both "must be viewed as supplements only. They do not replace good personal hygiene or the use of chemical-protective gloves" (OSHA manual).
• Wash fluid off skin periodically, especially before breaks and meals, with gentle soaps, clean water and clean towels.
• Never clean up with solvents, mineral oils or industrial detergents at the workstation, the manual says harsh cleansing can itself cause irritant dermatitis or worsen it.
• Change clothing that becomes soaked during the shift, wear clean work clothes every shift, and change into street clothes before leaving.

What to ask your supervisor for

Based on the OSHA manual and NIOSH 98-116, these are reasonable, specific requests to bring to a supervisor or safety lead:

1. The Safety Data Sheet for the fluid and any additives, so the right glove material can be chosen.
2. Chemical-resistant gloves matched to that fluid, and a clear rule on which operations allow gloves.
3. A concentration and pH check of your machine's sump against the supplier's recommended range, and tramp oil removal if the surface is oily.
4. Handwashing facilities close to the work, with gentle soap and clean towels, the manual warns that inconvenient washrooms push people to wash with solvents.
5. Splash guarding restored where it is missing, and fluid flow that does not run over unprotected hands when loading parts.
6. Barrier or moisturizing cream selected for the fluids in use, as a supplement.
7. A referral to a health professional if the rash persists, and inclusion in medical monitoring.

OSHA's manual recommends medical monitoring that includes a skin examination and skin history, at no cost to participating employees, and stresses that employers should actively encourage prompt reporting, because workers may hold back symptoms for fear of involuntary transfer or loss of income. The physician's report to the employer should only reveal findings related to occupational exposure. As an example of medical management, the manual cites reassigning a worker with serious dermatitis to an area with no skin exposure, combined with proper treatment.

If you want the exact wording to show your supervisor, on gloves, creams, or what makes a fluid irritating, the metalworking fluids knowledge base answers questions such as "Can operators just grab any pair of gloves when handling coolant?" with the OSHA passage quoted.