What are the HSE exposure limits for lead in work environments?

The Health and Safety Executive, in the UK establishes limits on exposure, at work to reduce health hazards.

Airborne lead exposure threshold;
The Workplace Exposure Limit (known as WEL) set at 0.15 mg/m³ of lead, in the air over an 8-hour timeframe is designed to regulate the amount of lead that can be inhaled by individuals, in the workplace.
Blood lead levels (abbreviated as BLL); Limits, for taking action, on blood lead levels.
 For the majority of employees, in the workforce the accepted threshold stands at 50 micrograms, per decilitre (µ g/dL). In cases where blood lead concentrations surpass this limit employers are required to implement measures to minimise exposure.

Women, in their childbearing years should be mindful of maintaining a blood lead level, below 25 (µ g/dL) to ensure the safety of their health and take precautions when necessary.
When blood lead levels exceed these limits, at work sites must take workers out of exposure. Conduct health checks regularly ensure health and safety standards are maintained by employers include checking lead levels in the workplace and using measures, like good ventilation protective gear and cleanliness procedures.