мои варианты:
Let the Safety Days Go!
Let the Safety Days Happen!

Может, еще что подскажете?

Заранее спасибо

Читали? Ни сада не было, ни города. Имелось ввиду, что когда-то они - будут, а пока давайте помечтаем. А у вас эти дни уже проводятся, они уже были, они есть. Поэтому "быть" у вас может только то означать, что идет какая-то борьба за выживание этих мероприятий.
Вот из этого и исходите при переводе

Статья из газеты предприятия?

See you at Annual Safety Days!

'See You at the (Annual) Safety Days!'

This is a good one, as you can't really translate it as 'Let the Safety Days [+ verb]' -- it doesn't sound English.

Also you have to be careful how and where you use it, as it's a well-known line from the Bible and the name of a song by Louis Armstrong which (I suspect) refers to it. Where were you thinking of using it?

???

//'Let the Safety Days [+ verb]' -- it doesn't sound English//
//Let my people go.// Does it sound English or not?
\\It's perfectly good English\\

Kind of dubious?

There are plenty of phrases which people use every day and which employ the construction 'Let the [noun]+[verb]', such as 'Let the games begin', 'Let the people decide', 'Let the detractors say what they like' etc. Some (like your 'Let my people go') are already extremely well-known, so if you use them you have to be aware of how they were used originally or how they're generally used today, and realise that if you include them, you risk creating an allusion to that use.

When it comes to '(Annual) Safety Days', it's such an obscure term that, even if you're trying to make it sound humorous, you risk it sounding very clumsy -- 'un-English' -- if you don't translate it very carefully. I couldn't think of a phrase using the 'Let the (A.)S.D. [+verb]' construction, inc the ones suggested so far, that didn't sound clumsy, so for that reason I played safe and opted for Denisska's version.

Although they did lots of good work, H&S people generally gained a reputation for being interfering, telling people the obvious (eg 'Don't stand in a bucket of water when you're using electrical equipment') and creating huge amounts of unnecessary paperwork for businesses. So, after a while, H&S was seen as a bit of a joke. Many people still think that way today.

H&S is now endemic in most companies. However, it's probably more because they're terrified of being sued than because they care for their staff!

ЗЫ. таки ценитель. неопечатка.

- и я бы разбил на два предложения.

в итоге (чисто вариант что-то типа):

(Join the) Industrial Safety Days. Let safety be the priority!

I'm not that good a linguist, just someone who (like most people on this forum) is interested in languages. I'm no good at translating into Ru, as it's something I've not done since I was a student. And, like most translators, there are lots of subject areas I know little/nothing about.

I'm not that clever compared to some of the people on this forum. I'm amazed at how complex some of the texts they have to translate are -- medical, legal and others -- and how they cope with them.

о таком дне известно заранее, и готовятся к нему тоже заранее: закупают накануне вдвое больше обычного, чтоб на оба дня хватило. таким образом в канун дня трезвости начинается вдвое более интенсивное употребление (его ж не остановить) - и как результат в день трезвости все вдвое более никакие.