I'm from the UK, visiting the US for a few months. I am allergic to biological laundry detergents. I can't seem to find any non-biological detergent available. Is it sold under a different term in the US? Is there a specific brand I should buy? Most of the ones I can find at the supermarket say somewhere on the back that they contain biodegradable surfactants and enzymes, which I assume means that they're what we would call biological in the UK, and would make me itch. Is this correct?
We do not use the terms "biological" and "non-biological" detergent in the United States. Instead, we label them enzyme detergents. They're mostly used in order to avoid things like having to presoak laundry (the proteins will help attack stains) or treating stains with another method.
If you are in a store or something, reading the labels on detergents will indicate if they contain anything like probiotic/enzyme/protein ingredients.
There are some brands that claim their products contain no enzymes or similar additives, including:
Planet Ultra Liquid Detergent - claims to have no dyes, fragrances, perfumes, or enzymes/proteins
Trader Joe's labeled laundry detergent
All Free and Clear (should be very easy to find anywhere)
Purex Ultra Hypoallergenic (though most Purex doesn't contain enzymes)
Typically, "Free and Clear" detergents probably won't contain enzymes, as they're meant to be hypoallergenic, but I would read the labeling to make sure.
So yes, seeing "enzyme" on the label means it's like 'biological detergent' in the UK.
Biodegradable is a different idea. Basically, biodegradable detergents do not contain ingredients that can not be destroyed if it were just poured out into the ocean or nature or something. Some detergents (mostly the mainstream major brands) contain stuff like dyes or fragrances which can't be broken down by natural means.