What is a key precaution when working with substances near their LEL?

When working with substances near their Lower Explosive Limit (LEL), ensuring proper respiratory protection is critical because these substances can create an explosive atmosphere if they reach a concentration that falls within their flammable range. The LEL represents the minimum concentration of a gas or vapor in the air that can ignite and cause a fire or explosion.

Using respiratory protection helps prevent inhalation of harmful vapors or gases, which may be present in higher concentrations near their LEL. In situations where flammable materials are involved, the risk of combustion increases dramatically, making it essential to have adequate protection against potential inhalation hazards.

Other options, while they may have their appropriate contexts in occupational safety, do not address the primary concern of working near LELs effectively. For example, standard gloves may protect against direct skin contact but do not mitigate the risk of inhaling vapors. Fluorescent lighting does not impact airborne concentration levels and manual handling techniques relate more to physical handling of materials rather than the responsive precautions necessary when dealing with flammable substances.