Over the past week I have asked Hewlett-Packard, Samsung, Microsoft, Dell, Amazon, Barnes & Noble and Lenovo about their reports on labor conditions. Many, if not all, of these electronics makers also use Foxconn.

Most responded with a boilerplate public relations message. Some didn't even respond. The answer from Barnes & Noble, the maker of the Nook e-reader, was typical. Mary Ellen Keating, a senior vice president, said only, "We don't comment on our supply chain vendors." Ms. Keating wouldn't say why Barnes & Noble does not discuss its manufacturing.

Lenovo e-mailed an off-topic report on sustainability.

Samsung, which sells far more cellphones than Apples does, gave no response.