Putting the Lid on Chemical Burns
Knowledge and protection can prevent serious hand injuries.
- By Nelson Schlatter
- Jan 01, 2011
We did not wear safety gloves back in the days when I was a student conducting experiments in our high school chemistry laboratory. Fortunately, when I splashed sulfuric acid on my forehead, I had the presence of mind to use water to immediately wash the chemical from my skin, thereby preventing a serious chemical burn.
Unfortunately, individuals working with chemicals in labs, processing plants, or during cleanup and maintenance may not be so lucky because chemical burns are not always obvious, and the individual's reaction to a substance may be delayed. Chemical burns (depending on the substance involved and the severity of the injury) can cause severe pain and suffering and can result in disfigurement, long-term disability, and even death.
Chemical burns are very different from heat burns in that they generally produce no heat, although the worker is likely to experience a burning sensation. The severity of a chemical burn will depend on the concentration of the substance to which the worker is exposed and his or her length of exposure.
Symptoms of workplace chemical burns include itching or skin irritation, pain or numbness, blisters, and/or bleached, reddened, or darkened skin. In more severe cases, victims may suffer from tissue necrosis. Exposure to corrosive vapors can cause victims to cough up blood or have difficulty breathing. Treating a chemical burn is a race with time because the longer the substance remains on the skin, the deeper the burn.
Chemicals That Burn
Chemical burns often result from exposure to strong acids and bases that are caustic and can cause significant tissue damage during even brief exposure. Bases typically result in more severe tissue damage than acids because they are more persistent during contact with the skin. A relatively quick rinse often can remove acids, but bases require a sustained body flush for as long as 20 minutes to prevent further harm.
The chemical groups that follow are often used in industry and can cause chemical burns:
- Sulfuric acid -- found in drain and metal cleaners, automobile battery fluid, munitions and fertilizer manufacturing, and many other products.
- Muriatic or hydrochloric acid -- used in products employed to clean brick and metal, etch concrete, and maintain pools. This is one of the most corrosive acids.
- Hydrofluoric acid -- found in rust removers and various cleaners; also used in refrigerant and fertilizer manufacturing and petroleum refining. This acid is extremely toxic.
- Nitric acid -- used in the production of numerous chemicals. This is a very strong acid.
- Phosphoric acid -- utilized for metal cleaning and refining, fertilizer manufacturing and rust proofing. It is also found in disinfectants and detergents.
Common bases or caustics:
- Sodium hydroxide and potassium hydroxide -- used in drain and oven cleaners.
- Sodium and calcium hypochlorite -- used in bleaches and swimming pool chlorinating solutions. Sodium and calcium hypochlorite are not only bases, but also oxidizing agents and can cause burns by more than one chemical mechanism.
- Ammonia -- used in many cleaners and detergents. Gaseous anhydrous ammonia may be found in various industrial applications, including fertilizer manufacturing.
Protecting Against Dangerous Chemicals
Gloves that provide protection against chemicals are generally categorized according to the materials used and whether they are supported or unsupported. In general, I recommend vinyl supported or neoprene supported gloves to protect workers against many of the substances mentioned in this article that can cause chemical burns.
Supported gloves are made by dipping a knitted or woven cloth liner into a glove compound, such as nitrile. The liner fabric then "supports” the compound and adds strength. Some supported styles have continuous coatings to ensure protection from chemicals. Supported gloves without continuous coatings, however, typically do not provide the high level of protection needed for applications with highly concentrated chemicals. These gloves are usually designed to improve grip and protect against cuts, abrasion, and other non-chemical hazards.
Unsupported gloves achieve their glove-shape by dipping hand forms directly into a glove compound without a supporting liner or fabric. These gloves offer a broad spectrum of chemical resistance based on the materials used to manufacture the product.
Below are specific materials that will protect against chemicals that could burn the skin:
- Poly Vinyl Chloride (PVC or Vinyl) -- often available in heavy supported styles; protects against strong acids and strong bases. Many PVC and vinyl gloves also protect against cuts and abrasion.
- Neoprene -- available in disposable, medium weight unsupported, medium weight supported, and heavy weight supported styles. These gloves are medium cost and protect against common oxidizing acids (nitric and sulfuric) and many other chemicals.
- Poly Vinyl Alcohol (PVA) -- used for medium weight supported gloves that are highly resistant to many organic chemicals. PVA gloves are ineffective against the acids and bases mentioned in this article. But they are very effective against organic chemicals, such as chlorinated solvents and aromatic compounds, some of which can cause skin burns.
- Sealed-Film (Laminate) -- represents one of the most chemical-resistant materials available and protects against almost anything. These gloves are excellent for hazmat applications in which the chemicals present may be in question. Laminate gloves fail to provide a close fit, a good grip, or strong physical properties. Fortunately, laminate gloves are quite thin and are commonly worn as liners under other gloves that can protect in ways that laminate gloves cannot.
Aprons, overalls, coveralls and jackets are available that are made of vinyl and other fabrics, such as CPC® polyester and Nomex® Trilaminate, which is made with chemical-resistant fluoropolymer film and polyester or Nomex. These garments protect the arms and torso against chemical splash.
Silver nitrate, lye, and lime also can cause chemical burns.
An Ounce of Prevention
The old adage "an ounce of prevention is worth a pound of cure" certainly applies to chemical burns. The best way to prevent serious burns is to avoid contact with dangerous chemicals. If contact does occur, workers should be wearing the proper protection, including apparel, gloves, goggles, and masks.
Because many chemical burns occur on the hands and arms, wearing protective gloves and apparel is a primary line of defense. Safety personnel who select protective apparel and gloves should know not only the name of the chemical to which workers are exposed, but also other important details, such as the possible length of exposure and the chemical's concentration.
Companies sometimes over-specify gloves that protect against chemicals, which can be expensive. A worker who is exposed to a diluted chemical for a short period of time, for example, will require less protection than an individual charged with pulling samples of highly concentrated chemicals for testing at a fabricating plant.
Phosphoric acid is an excellent example because it is a hazardous chemical in concentrated form. When it is greatly diluted, it serves as an important ingredient in cola drinks. The diluted form is obviously much less toxic than the concentrated form.
Many manufacturers and universities offer chemical resistance guides to help laboratories and manufacturing plants select gloves and clothing that provide the level of protection required against specific substances. Ansell's SpecWare® application, available free at www.ansellpro.com, is an example of a widely used chemical resistance guide.
The Race for Treatment
Prevention should be the first line of defense against chemical burns. Plant workers and supervisors should know which chemicals are being used within their facilities and at what concentrations. They should also familiarize themselves with the Material Safety Data Sheets for specific chemicals and the recommendations for personal protective equipment. Treatment and antidotes must be readily available to workers.
Any chemical burn, no matter what the size, should be considered serious because the extent of the burn often depends on how long the chemical remains on the skin. Every second counts.
Most industrial sites are equipped with emergency showers. Workers should know the showers' location and be able to reach a site within seconds. They should remove contaminated clothing and remain in the shower for at least 20 minutes. An appropriate neutralizing agent (if available) should be applied to the skin.
Burn victims should seek medical attention as soon as the burn has been completely flushed and all contaminated clothing removed. A quick response followed by the proper medical treatment could keep a chemical splash from becoming a serious, disfiguring burn.
New Template to Improve Cut Protection Testing
Jeff Moreland, Ansell technology solutions scout in Pendleton, S.C., worked out a new template for testing cut-resistant gloves that will clarify the test method specified in ANSI/ISEA 105-2005 American National Standard for Hand Protection Selection Criteria (www.safetyequipment.org/c/std105-2005.cfm).
This ISEA standard ranks gloves' cut resistance from 0 to 5. Manufacturers self-certify their own products, Moreland said. However, ASTM oversees the test method (ASTM F1790 - 05 Standard Test Method for Measuring Cut Resistance of Materials Used in Protective Clothing, www.astm.org/Standards/F1790.htm) that is referenced in ISEA's specifications.
Moreland is subcommittee chairman for the ASTM committee that addresses the test method. He said manufacturers currently use an Excel spreadsheet and input their data into it to get their ratings; the question was why ASTM had not provided a spreadsheet for this. "I think it was no one wanted to put all the effort into doing it," he added.
ISEA and ASTM were not in sync on their revision schedules for this issue, Moreland explained. ISEA until now was referencing an old ASTM method, which caused confusion as new entrants used newer ASTM methods. With ISEA interested in issuing its own, Moreland developed the spreadsheet and also devised some suggested changes to the ASTM method to ensure everyone tests the same way. The ISEA draft document was at the final approval stage when the 2010 National Safety Congress & Expo took place in October.
Moreland said the new template allows manufacturers to test products to the old method and the new one, which will be good for five years. This is important, he said, because companies such as Ansell have a lot of historical data from the old method. Those who want to test using the old method still can.
The spreadsheet will clarify and simplify reporting, and its format makes it easy for a user to know a glove's protection level. "We're providing this essentially as a service to the industry," he said. "Somebody had to step up and say, 'I'm going to do this.' " He said it is based on a template he'd created internally but is more user friendly than the internal version and is set up for three samples. The spreadsheet will be available to download and use from ISEA's site as the test method for 105 for cut protection.
The new method under-reports cut protection capability a bit, he said. It will be more economical for manufacturers, said Moreland.
This article originally appeared in the January 2011 issue of Occupational Health & Safety.