I have just returned from Mexico, where I visited a factory making medical masks. Faced with fierce competition, the owner has cut his costs by outsourcing some of his production. Scores of people work for him in their homes, threading elastic into masks by hand. They are paid below the minimum wage, with no job security and no health care provision.

Users of medical masks and other laboratory gear probably give little thought to where their equipment comes from. That needs to change. A significant proportion of these products are made in the developing world by low-paid people with inadequate labor rights. This leads to human misery on a tremendous scale.

Take lab coats. Many are made in India, where most cotton farmers are paid an unfair price for their crops and factory employees work illegal hours for poor pay.

One-fifth of the world's surgical instruments are made in northern Pakistan. When I visited a couple of a years ago I found most worker toiling 12 hours a day, seven days a week, for less than a dollar a day, exposed to noise, metal dust and toxic chemicals. Thousands of children, some as young as 7, work in the industry.

To win international contracts, factory owners must offer rock-bottom prices, and consequently drive down wages and labor conditions as far as they can. We laboratory scientists in the developed world may unwittingly be encouraging this: we ask how much our equipment will cost, but which of us asks who made it and how much they were paid?

This is no small matter. Science is supposed to benefit humanity, but because of the conditions under which their tools are made, many scientists may actually be causing harm.

What can be done? A knee-jerk boycott of unethical goods is not the answer; it would just make things worse for workers in those manufacturing zones. What we need is to start asking suppliers to be transparent about where and how their products are manufactured and urge them to improve their manufacturing practices.

It can be done. Many universities are committed to fair trade in the form of ethically sourced tea, coffee or bananas. That model should be extended to laboratory goods.

There are signs that things are moving. Over the past few years I have worked with health services in the UK and in Sweden. Both have recently instituted ethical procurement practices. If science is truly going to help humanity, it needs to follow suit.