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Warning: This product can expose you te chemicals including lead, which are known to the State of California to cause cancer.

I recently purchased a midtier USB audio interface which I found this warning. Would it be safe to assume that the product just uses lead solder? I know there are sensitive analog components here -- if they didn't use leadfree solder is it due to a design choice for audio applications or just because they don't care about ROHS and the European market. From I understand, lead solder is better understood but for most applications, they are equivalent functionally (minus operation in space)?

I am interested if anyone from industry has input on the design choices of lead vs lead free solder.

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    \$\begingroup\$ This product <i>can</i> expose you. This is lawyer speak for 'If you see this, you can't sue us'. If it complies with RoHS, it has negligible amounts of lead and other dangerous chemicals. \$\endgroup\$ – Lior Bilia Mar 21 '20 at 18:34
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    \$\begingroup\$ That is a generic warning that Califronia requires on almost everything. The sentence below the warning box says the lead content of the product complies with RoHS and California regulations. \$\endgroup\$ – Peter Bennett Mar 21 '20 at 18:41
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    \$\begingroup\$ Sometimes it's actually in the insulation and not the solder. \$\endgroup\$ – DKNguyen Mar 21 '20 at 21:32
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Lead solder has two main advantages over lead free solder:

  1. It flows at a lower temperature which causes less stress for the electronic parts and the pcb due to a decrease in thermal expansion in comparison with lead free solder
  2. Lead seems to mitigate the formation of tin whiskers; a crystalline growth that can cause short circuits in your design

The biggest disadvantage of lead solder is that it's bad for the health of a lot of organisms. Preventing products from using lead also prevents it from ending up in land fills which causes less exposure in general.

Whether it's safe to assume that the product is only using lead solder can probably not be answered from that picture alone.

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Big picture: you are not at meaningful risk from lead exposure from this product.

The Prop 65 warning is a catch-all that includes any potentially harmful chemical. Unfortunately, it's so overused that it has lost its meaning and intent. It does not mean that the component contains lead; and it likely doesn't because...

... the RoHS compliance statement is based on quantitative analysis of the product and the components that are used to make it, and applies specific (and very low) limits for a list of hazardous substances, including cadmium, lead and others.

More here: https://www.nist.gov/standardsgov/compliance-faqs-rohs

The RoHS and California lead limit is 1000ppm (0.1%) by weight.

Where does lead show up? Not in solder, generally. It is sometimes used for mounting high-power / high temperature chips on substrates, but even this use is rare anymore. Lead is sometimes used in wire insulation to make the cord more pliable (think light strings from China) but this use would not meet RoHS.

More about the exemptions here: https://www.rohsguide.com/rohs-lead-exemptions.htm

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