Chemical hazards: Acids and Caustics

When conducting a workplace risk assessment, you’ll likely uncover a few chemical hazards. Once engineering and administrative controls have been addressed, choosing the right PPE will be an important step in protecting employees who handle or are exposed to those chemicals.

Chemicals are not necessarily dangerous if they’re used as directed, although misuse or accidental exposure can still occur. An even more hazardous situation is when there is an accidental release, such as a spill, container rupture, or a failure of chemical lines or systems. Any release will require appropriate handling, clean-up, and disposal. Properly identifying the chemical and obtaining the right Safety Data Sheet (SDS) will provide direction in how to safely address the situation.

Chemical types

The right protection level for handling chemicals is based on the chemical’s type and strength (concentration). You can determine whether a chemical is an acid or caustic by its potential of Hydrogen (pH) as it dissolves in water. The pH scale ranges from 1-14, with water being neutral (neither acid or caustic) at 7.0. The greater the number of Hydrogen ions, the more acidic the chemical. Fewer Hydrogen ions makes the chemical a caustic – also referred to as a ‘base’ or ‘alkaline.’

Both acid and caustic chemicals are corrosive. The further the pH is from water at 7.0, the more corrosive it is. The higher the concentration of the chemical, the more corrosive it is. If the chemical is diluted with water, it’s still corrosive, but has a less severe reaction.

Acids

An acid is a chemical compound with a pH lower than 7.0, making it acidic. It produces H+ (Hydrogen) ions when dissolved in water. Acids are generally used in cleaning agents, reacting with metals, as well as clothing materials and skin, depending on the strength or concentration. Commonly used acids include Hydrochloric (muriatic), Sulfuric, Nitric (fertilizers and explosives), Carbonic (carbonation in soft drinks), Acetic (vinegar), and Citric (natural in citrus fruits). An acid, by definition, is something that produces a sour taste, reacts with (corrodes) metals. When introduced with mild caustics, salt compounds are produced. Many of these compounds are also used as fertilizers to feed plants that thrive in acidic soil.

Caustics

A Caustic, also referred to as a base or an alkaline, is a chemical compound with a pH greater than 7.0. It produces OH- (hydroxide) ions when dissolved in water. It’s defined as a substance that can burn, corrode, or destroy organic (carbon-based) tissue. A caustic can also be used as a cleaning agent, as a degreaser, used in industrial processes, and used to make soaps and detergents. Common caustics include Sodium Hydroxide (lye), Potassium Hydroxide (potash), and Calcium Hydroxide (slaked or quick lime). Caustic substances have a bitter taste rather than a sour taste.

As a quick reference, any chemical ending in “hydroxide” is a caustic.

Harmful properties of chemicals

Strong acids (lower pH numbers 1-3) can burn skin as it reacts with water (sweat). They can also combine with other incompatible chemicals during an incidental spill or rupture to produce corrosive gases that can be inhaled. If splashed or sprayed around mucous membranes (eyes, nose, mouth), they can cause harmful effects from irritation to serious burns. Acids are exothermic, meaning when chemically reacting, a byproduct is the release of heat. This action can create fire and explosions in addition to forming corrosive gases.

Strong caustics (pH numbers 10-14) are harmful, as they can get absorbed under the skin and react with insulating fat cells. If contacting mucous membranes, the depth and severity of the burn is greater than that of an acid.

Both acids and caustics require PPE when handling them to ensure skin, eyes, and face are protected. Depending on the location and use of these chemicals, adequate ventilation is essential to ensure clean, breathable air as well as removal of any build-up of vapors or heat-producing reactions.

Hazards to humans

Though acids and caustics react differently, exposure can result in the same type of chemical burn injury. The difference is whether it’s an acid that will immediately begin to burn on the skin or a caustic that may take a couple of minutes to start reacting with the person’s fat tissue under the skin.

Mucous membranes, as mentioned above, are also at risk. The eyelids as well as the fluid in the eyes, the lining of the nose, and the lining of the lips and mouth can be seriously impacted if exposed to the chemicals. Fine mists that remain suspended in air can also irreparably damage the bronchi and lungs.

Absorbing chemicals through the skin can create varying forms of cancer or organ disease, such as to the liver, pancreas, and colon.

There is significant risk of infection if treatment – such as immediate flushing of the exposed areas with copious amounts of water or additional treatment needed by a healthcare provider – is delayed. Exposures can be costly for the injured employee. Disruption in wages to adverse changes to the employee’s or family’s quality of life are just a couple examples.

Additional costs include the need for treatment and rehab, follow-up physician visits, potential of surgery for skin grafting, etc. All these costs will also impact the employer.

Consider this: exposed skin that produces dermatitis averages $22,000 in treatment costs. If the exposure produces a skin burn, the cost exceeds $99,000; and, once infected, depending on the amount of skin surface involved, the cost is at least $65,000 in addition to the initial treatment of the burn or irritation point.

Protective measures

Mechanix Wear, a global PPE manufacturer, uses the latest in technological advances in designs and fabrics for best-in-class personal protection without compromising productivity. Partnering with employers allows the PPE experts to identify and provide real-world solutions to workplace and employee hazards by listening and observing onsite how the hazards impact employees.

Mechanix Wear offers an array of chemical-resistant gloves and chemical-protective apparel that is compatible with the type of chemical exposures identified in the workplace.

Chemical protection standards

Mechanix Wear manufactures its chemical-resistant gloves and apparel following established international standards to ensure employees exposed to chemicals are properly protected. Glove standards include both European (EN ISO 374-1:2016) and US (ANSI/ISEA 105-2016). Apparel standards include EN 14325:2017 and ISO 16602. As a side note, a new ISO 17723-1 (still in draft mode) will address chemical protection ensembles specifically related to emergency response teams.

Additional chemical apparel standards include ISO 27065-2017, European directives (EU 2016/425, EU 89/656/EEC, EU 89/686/EEC), and US consensus standards (ASTM, NFPA).

Protection levels

The standards test glove and apparel materials for penetration (holes, leaks), degradation (adverse reaction to the chemical), permeation (time it takes for chemical to break through), and micro-organisms (bacteria, fungi).

Protection levels and labeling must include identifying the chemical(s) for which the glove or apparel is designed.

No chemical glove or apparel can protect from all levels of chemical risk because of:

• Exposure scenarios
• Chemical properties
• Types of barriers provided on the material/fabric
• Strength/concentration of the chemical
• Time duration of exposure
• Garment or glove construction (seams, closures)
• Environmental conditions (temperature)

To help determine the right fabric or material to protect from chemicals, it’s wise to use a chemical compatibility chart. Such a chart does not contain all chemicals as new ones are created every day. Identifying the chemical’s properties can assist in making the right decision as well as referencing the chemical’s Safety Data Sheet (SDS).

Additional chemical PPE needs

There may be additional personal protection needs depending on the identified hazards uncovered in your location’s risk assessment. Consider:

• Chemical protective eyewear and face shields
• Respiratory protection, which will require an OSHA written plan
• Chemical-resistant safety footwear, such as rubber boots
• Chemical-resistant sleeves, footies, hoodies

Other concerns and consequences include a puncture, leak, or release of liquid pressurized chemicals, locking out or ‘blinding’ chemical lines prior to maintenance, moving/transporting totes or bulk tanks of chemicals, loading/unloading of tankers or railcars with high volume and high concentration of chemicals, and other hazards found in your risk assessment.

Any of these issues can also result in environmental or community concerns. Pre-planning and training with an internal or external response team along with employee knowledge and defensive response to protect drains, culverts, ponds, and groundwater must be considered. In these types of events, compatible PPE is necessary as is having the right absorbing or diverting materials, which may differ, depending on the amount, concentration, and type of chemical released.

Summary

Most industries and locations will have some type of chemical delivered, stored, handled, and disposed of in which chemical-resistant PPE, training, and procedures are necessary to keep people, property, and the community-at-large safe and healthy.

Your first stop in your chemical protection needs should be the chemical’s Safety Data Sheet (SDS) to train employees on the use, hazards, response, and protection requirements, which keeps your employees safe and healthy while complying with OSHA’s Hazard Communication Standard (29 CFR 1910.1200).

Various local, state, and federal agencies and trade associations are available to assist in identifying hazards that may be unique to your industry. Mechanix Wear, with its PPE experts, can assist in identifying the right PPE solutions for your specific onsite hazards.

You can contact Mechanix Wear today through its TRACK program to partner with the professionals and ensure you select, trial, and use the right PPE for the specific hazard. With a Mechanix Wear partnership, you can rest assured that your employees are properly protected and productive through proper fit, form, and function of the PPE.