What defect might occur due to exposure to chemicals or petroleum in rubber insulating gloves?

When rubber insulating gloves are exposed to chemicals or petroleum, one of the most significant defects that can occur is hardening. This hardening is often a result of the rubber deteriorating due to the chemical composition of the substances it comes into contact with. Chemicals can break down the elastic properties of the rubber, leading to a loss of flexibility and pliability, which is crucial for the effectiveness of the gloves in providing protection.

Hardening compromises the gloves' ability to conform to the wearer’s hands, increasing the risk of tearing and reducing overall effectiveness in preventing electrical hazards. This change in the material properties can significantly hinder the safe use of the gloves in electrical work or other applications where insulation is vital for safety.

While surface cracking, shrinking, and swelling may also be potential defects resulting from various environmental factors, in the context of chemical or petroleum exposure, hardening is the most prominent and direct consequence affecting the performance and safety features of rubber insulating gloves.