Solders are mixtures of metals such that the melting point of the mixture is below that of the constituent metals (normally lead and tin). Solder application does not normally give rise to toxic lead fumes, provided a gas/air flame is used.
Oxy-acetylene flames should not be used, as they are much hotter and will cause lead fumes to be produced.
Some fumes may be produced by the application of any flame to surfaces coated with grease, and inhalation of these should be avoided.
Removal of excess solder should be undertaken with care, to make sure that fine lead dust is not produced, which can give toxic effects if inhaled.
Respiratory protection may be necessary.
Solder spillage and filings should be collected and removed promptly to prevent general air contamination by lead.
High standards of personal hygiene are necessary in order to avoid ingestion of lead or inhalation of solder dust from clothing.