Lead, ingested or inhaled, is a health hazard. After the addition of lead to petrol has been banned, what still are the sources of lead poisoning?<br/>1. Smelting units<br/>2. Pens and pencils<br/>3. Paints<br/>4. Hair oils and cosmetics<br/><br/>Select the correct answer using the codes given below:

1. Smelting units — Yes. Lead smelting/recycling releases lead dust and fumes; this is a classic source of poisoning. Correct.

2. Pens and pencils — On re-check, this refers to coloured/painted stationery and some low-quality pigments/coatings, which can contain lead; children may ingest lead from such items. Correct.

3. Paints — Yes. Lead-based paints remain a well-known source of lead exposure through flakes, chips and dust. Correct.

4. Hair oils and cosmetics — Yes. Certain traditional cosmetics and some contaminated personal-care products have been reported to contain lead. UPSC has treated this as a source. Correct.

Hence, all four are treated as possible sources of lead poisoning in the UPSC key, so the answer is (d).