Should we vent our attic for new polyurethane closed-cell spray foam insulation?
All right. As soon as you see a headline beginning with "Losing Their Health and Homes to..." you should know that last thing the author has in mind is making your life better. The article is nothing more than atrocious clickbait. Do not make fundamental changes in your life or your home based on what somebody wrote purely to sell internet advertising.

Now, the EPA article can be trusted. But Margaret Badore, the author of "Losing Their Health...", is citing it in support of her super scary thesis. Does the EPA article actually say that SPF in your home is dangerous? It does not. Does the EPA article say you should be worried about SPF in you home? It does not. What it says is that the EPA is not absolutely certain that SPF poses no long-term danger.

In other news, the EPA is also not absolutely certain that composition decking, gas water heaters, iron nails, and NEST thermostats pose no long-term danger. Citing this EPA article in support of the long-term dangers of SPF is a pure and simple lie.

Badore gives the following evidence that SPF can cause health problems:


  [Mr. Rimel] came down with respiratory symptoms [after visiting] the
  construction site of their new home where a contractor was installing
  spray polyurethane foam insulation.


and:


  A couple in their 30's returned to their home four hours after spray
  foam was installed in the attic [and] almost immediately began
  experiencing difficult breathing, coughing, nausea, headaches and
  watery eyes.


Really. More than half of the text in the EPA article consists of every kind of warning against doing either one of these incredibly stupid things. Meanwhile Badore completely ignores the tens of millions of families happily occupying SPF-insulated homes with no ill health effects whatsoever.

The remainder of the EPA page is divided between (1) we don't know about the long-term effects and (2) removing the stuff usually makes the problem worse.

And the Rimels? Well, they searched out a company to test the site and guarantee its safety. Predictably, the testing company basically condemned the property. The Rimels panicked and removed the foam. It didn't help. The partially finished house had become haunted, for the Rimels and for anyone else who read the super scary test results.


  After months of being unable to find a satisfactory solution, they
  sold the property.


Don't be like the Rimels.