Hi prd,
It causes Hydrogen Embrittlement which really requires the steel to be heat treated to relieve the stress created in the metal. Basically it makes steel far more brittle and induces a situation like what the Titanic suffered from when it hit the iceberg.
Certainly not good for anything of a tensile nature but normal mild steel that isn't under any tensile strength is ok.
Being an Electroplater by trade this was a common issue with anything that wasn't used in a standard mild steel application.
Cheers,
BB.