Learn About Chemical Hazards
Who Needs Chemical Protection?
There are many applications throughout multiple industries where chemicals are used or produced in liquid or dust form. Some examples include:
- Solvents used in pants and cleaning fluids
- Asbestos and silicone dusts
- Feedstock and catalytic products used in chemical industries
These all present a range of health hazards to workers.
Chemical protective clothing is designed to protect the wearer from dermal contamination. Consequences of dermal chemical contamination range from minor skin irritation and skin burns, to, where chemicals can absorb into the body through the skin, a range of adverse health effects – including damage to organs and cancers.
A secondary requirement of chemical protective clothing may also be protecting against the contamination of a wearer’s normal clothing. Some substances, especially dust, may be later inhaled or touched after the protective PPE is removed. When a worker is dealing with asbestos, for example, the dust is harmful only if inhaled; but secondary contamination, where dust contaminating normal clothing is inhaled by the worker or those they encounter after the protective clothing has been removed, is a common problem.
Understanding Chemical Hazards
Chemicals are varied in nature, so it’s vital for safety managers and wearers of chemical protective clothing to have a thorough understanding of the hazards present when selecting PPE.
Unlike most workplace hazards, the consequences of coming into contact with chemicals may not be immediate – or even noticed. This doesn’t diminish the catastrophic health effects that can present months, years, or even decades later.
You can read more about the insidious nature of chemical hazards here and about how this affects management of chemical suits on site here.
Chemicals may enter the body via three routes:
- Absorption through the skin
The purpose of chemical protective clothing is to prevent contamination of the wearers skin or clothes. Preventing the ingestion or inhalation of chemicals is the purpose of other PPE, often worn in conjunction with chemical protective clothing.
Chemicals may be in liquid, dust, or gaseous/vapour form, each presenting different challenges for protection, resulting in different choices of garment. They may also change state in use (liquid becoming vapour) as temperature changes.
Chemical toxicity – the mass or volume of a chemical that is absorbed into the body and is likely to result in harm – is important in assessing the effectiveness of chemical protective clothing and in judging how long clothing can be safely worn if contaminated.
Routes of Chemical Contamination
The macro-level process when a dust or liquid passes through holes or gaps in the structure of the suit fabric, or through gaps between the suit and other PPE. Protection results from the fabric type and the coverall design and construction. Penetration generally deals with larger, visible volumes and is therefore an issue more concerned with lower-toxicity chemicals that are harmful in larger volumes.
The micro-level process by which the molecules of a liquid or gas (rarely dusts) pass between the molecules of a substance, thus passing through an apparently “solid” barrier, such as a chemical suit fabric. Resistance to permeation is a function of the polymers used in the fabric, which dictates the choice of chemical protective clothing. The rate of permeation varies with different chemicals and occurs in very small volumes measured in Micrograms (µg). Permeation is an inevitable process that cannot be prevented, only delayed or slowed. Many chemicals are harmful in very small volumes, so assessing permeation resistance specific to each chemical is vital in selection of chemical protective clothing.
The video below graphically outlines the difference between penetration and permeation
Interpreting Chemical Permeation Data
Permeation test result data is commonly misinterpreted as an indication of how long a suit can be used, leading to an assumption of safety which may be incorrect.
You can read about this common misinterpretation here and about how to correctly assess chemical safe-wear times here. Lakeland’s free smartphone app, PERMAsure®, provides a quick and easy method of assessing safe wear times for over 4,000 chemicals.
Types of Chemical Suits
Different types of chemical suits are defined by the type of protection they provide according to chemical state, volume, or pressure of spray or splash, level of toxicity, and the hazard risk. U.S. OSHA (Occupational Safety & Health Administration) protection levels and European EN protective clothing standards provide good guidance.
OSHA defines four general levels of chemical protection with a priority given to respiratory hazards, the highest being Level 1 for protection against gases and vapors.
EN Standards define different “types” of protection according to the state and spray type of liquid chemical.
In general terms there are three types of chemical suits available:
These are fully encapsulating, gas-tight suits with breathing air supplied from a self-contained breathing apparatus (SCBA) worn either inside or outside the suit.
OSHA Level 1/EN Type 1 chemical suits are generally constructed with multi-layer polymer barrier films that offer high resistance to heavy-duty chemicals and feature fully sealed seams.
These chemical suits are usually designed as one-piece coveralls with an attached hood and are often worn with a respiratory mask and other PPE, such as gloves and boots. In EN standards, the difference between Type 3 and Type 4 chemical suits is determined by the type of liquid spray, with Type 3 being for strong, pressurized jet-sprays and Type 4 for low pressure “shower” type sprays. You can read more about this here.
Garments constructed with polymer films to resist permeation have no breathability. Lighter weight garments are commonly single layers, while chemical suits to protect against more challenging chemicals will consist of multiple layers of specialist films. These garments are commonly primarily assessed by permeation resistance.
OSHA Level 3 / EN Type 5/6 chemical suits are generally one-piece coveralls with or without attached hoods. Fabrics are lightweight and disposable (these suits are commonly referred to as “disposables”), with some level of air permeability that varies considerably with different fabric types.
In fact, there are only three different fabric types in use for this type of chemical suit – only one of which is truly breathable.
These garments are used where there is little or no risk of contact with hazardous chemicals. They refer to standard work overalls or disposable coveralls made of light, single-layer nonwoven polypropylene.
Protective Clothing Standards
In North America, the OSHA levels described above represent the sole guidance for chemical suits and related PPE selection. However, EN standards are more extensive, providing detailed prescription of garment construction and design requirements according to protection type (described above), along with mandatory testing of fabrics and garments.
While EN standards are developed by and considered mandatory for the European Union, they are increasingly applied in many other regions, including Latin America, the Middle East, Asia, and Canada.
You can read more about the differences between EN chemical suit standards and OSHA chemical protection levels here.
Testing in CE protective clothing standards falls into three categories:
Strength profile testing of fabrics includes abrasion resistance, tensile and tear strength, puncture resistance, and flex cracking resistance. These are required for all types of chemical suit and provide a profile of fabric strength and durability.
You can discover more about fabric physical properties and where to find data here.
Resistance to Penetration or Permeation of Chemicals. These consist of two types:
Resistance to Permeation: (EN 6529 or ASTM F739). Assessing the effectiveness of resistance to permeation of specific chemicals. Used for OSHA level 1 and 2 and EN Type 1, 3, and 4 garments.
Resistance to Penetration: (EN 6530 or ASTM F903). Assessing effectiveness of resistance to penetration and the fabrics ability to repel liquids.
Whole Garment “Type Tests”
In accordance with EN “type,” whole garment type tests subject chemical protective clothing to sprays of liquid or dust to gauge the suit’s effectiveness in preventing contact with a contaminant. EN standards define minimum performance and produce a pass or fail result. EN CE certification requires a pass.
You can discover more about chemical protective clothing standards, including how EN standards and OSHA protection levels compare here, as well as how reflective they are of real-world conditions in this article.
You can find out more about the EN "Type Tests" here.
Donning and Doffing of Chemical Suits
Appropriate donning and doffing procedures are important in ensuring protection is maintained. A chemical suit not donned properly may not protect, while doffing may be a hazardous process itself if the suit is contaminated.
Experts recommend establishing written donning and doffing procedures with regular training for staff. You can read more about creating and strengthening donning and doffing procedures here.
Comfort and Chemical Protective Clothing
Comfort is an important issue for all types of PPE – but especially for chemical protective clothing. Providing uncomfortable garments to your employees often results in improper wearing, leading to less protection.
Investment in comfort is worthwhile. You can discover the benefits of more comfortable protective clothing here and read about ways to enhance comfort here.
Reusable or Disposable Chemical Suits?
In the case of chemical protection, deciding between reusable or disposable chemical suits can be misleading for one simple reason; permeation. The general rule should be that no suit that is either damaged or contaminated should be re-used.”
Once a suit is contaminated with a chemical, it is almost impossible to know if it remains trapped in the molecular structure of the fabric (even if it has not permeated through). If the suit is contaminated, then the chemical may seep out later, causing a potential hazard during doffing and donning or resulting in faster permeation when next contaminated. It could also combine with other chemicals if a suit is re-used for other protection – with unpredictable consequences.
For this reason, a contaminated suit should not be reused – regardless of its designation as disposable or reusable.
Whether any suit can be reused or not is subject to the circumstances. Reuse is always a risk and should only be approved by qualified safety personnel following a suitable risk assessment.
Lakeland’s ChemMax® chemical suits provide a comprehensive range of protection against most chemicals in use. You can read a comprehensive guide to ChemMax® here.