Think for a minute about why they worked in shacks.
Also worth noting that Birren was a paid consultant for DuPont - the company that made the paint. From that perspective alone you would kinda expect he is gonna pick colours they already produce reliably at scale.
He also consulted for army, coast guard and navy so whatever colours you pick for hazard marking in an industrial setting have to be _vaguely_ congruent or you're going to cause accidents.
Also worth noting that Birren was a paid consultant for DuPont - the company that made the paint. From that perspective alone you would kinda expect he is gonna pick colours they already produce reliably at scale.
He also consulted for army, coast guard and navy so whatever colours you pick for hazard marking in an industrial setting have to be _vaguely_ congruent or you're going to cause accidents.