Workforce Data for Legal Marijuana States 
Data provided by US Bureau of Labor Statistics:  Source

We decided to measure from 2008-2018 since most states legalized somewhere in between and this gives a good sense of before and after. We measured total numbers and per capita (as indexed to population) since some states have added millions to their population.

As you can see, marijuana legalization has not negatively impacted work safety in these legal states. In most cases, work related deaths and time missed to injury and illness have declined since 2008.

COLORADO  
FATAL WORK INJURIES PER CAPITA
(lower number is better)
2018 - 2.6 source  (Down 61% since 2008) 
2017 - 2.2 source 
2016 - 3.0 source
2015 - 2.9 source
2014 - 3.3 source
2013 - 2.7 source  * LEGALIZED
2012 - 3.5 source 
2011 - 3.9 source
2010 - 3.7 source
2009 - 3.4 source 
2008 - 4.2 source 

COLORADO
FATAL WORK INJURIES RAW DATA
(lower number is better)
2018 - 72   source  (Down 31% since 2008)
2017 - 77  source
2016 - 81   source  (Pop. 5.541 million)
2015 - 75   source 
2014 - 84   source
2013 - 65   source  *LEGALIZED
2012 - 82  source 
2011 - 92  source   (Pop. 5.122 million)
2010 - 85  source
2009 - 83  source
2008 - 105 source 
2007 - 126 source
2006 - 137 source   (Pop. 4.748 million)

COLORADO
WORK ILLNESS AND INJURY RATES PER CAPITA

**Colorado does not provide this dada

WASHINGTON
FATAL  WORK INJURIES PER CAPITA 
(lower number is better)
2018 - 2.4  source  (Down 7% since 2008)
2017 - 2.5 source
2016 - 2.4 source 
2015 - 2.1   source 
2014 -  2.7  source * stores open July 
2013 - 1.7   source * LEGALIZED
2012 - 2.2 source  
2011 - 1.9 source
2010 - 3.4 source
2009 - 2.5 source
2008 - 2.6 source

WASHINGTON
FATAL WORK INJURIES RAW DATA
(lower number is better)
2018 - 86 source  (Up 2% since 2008)
2017 - 84 source
2016 - 78 source  (Pop. 7.295 million)
2015 - 70 source
2014 - 88 source  * Stores open July 
2013 - 56 source  * LEGALIZED
2012 - 67 source   (Pop. 6.893 million)
2011 - 60 source  
2010 - 104   source  
2009 - 76 source
2008 - 84 sourc (Pop. 6.566 million)

WASHINGTON
INJURY AND ILLNESS RATES PER CAPITA
(lower number is better)
2018 - 4.2 XLSX (Down 26% since 2008)
2017 - 4.2 XLSX
2016 - 4.4 XLSX
2015 - 4.5 source
2014 - 4.7 source   * Stores open July 
2013 - 4.9 source   * LEGALIZED
2012 - 5.0 source
2011 - 5.1 source 
2010 - 5.0 source 
2009 - 5.3 source 
2008 - 5.7 source

OREGON
FATAL WORK INJURIES P ER CAPITA
(lower number is better)
2018 - 3.1   source  (unchanged since 2008)
2017 - 3.2   source
2016 - 3.9   source 
2015 - 2.6  source  * LEGALIZED
2014 -  3.9  source 
2013 - 2.9  source 
2012 - 2.6   source  
2011 - 3.4   source
2010 - 2.9   source
2009 - 3.9   source
2008 - 3.1  source

OREGON
FATAL WORK INJURIES RAW DATA
 (lower number is better)
2018 - 62  source (increase 12% since 2008)
2017 - 60  source (pop 4.191 million)
2016 - 72  source  
2015 - 44  source  *LEGALIZED
2014 - 69  source 
2013 - 49  source 
2012 - 43  source  (pop 3.899 million)
2011 - 58  source  
2010 - 47  source  
2009 - 66 source 
2008 - 55  source 
2007 - 69 source (pop 3.731 million)

OREGON
WORK ILLNESS AND INJURY RATES PER CAPITA
 (lower number is better)
2018 - 3.7  XLSX (down 21% since 2008)
2017 - 3.8  XLSX
2016 - 4.0  XLSX
2015 - 3.8  source *LEGALIZED
2014 - 4.0  source
2013 - 4.1  source  
2012 - 4.0 source
2011 - 3.9  source 
2010 - 4.0 source 
2009 - 4.5  source 
2008 - 4.7 source

CALIFORNIA 
FATAL WORK INJURIES PER CAPITA
 (lower number is better)
2018 - 2.3  source (down 17% since 2008)
2017 - 2.2  source * LEGALIZED
2016 - 2.2  source 
2015 - 2.2  source  
2014 - 2.0   source 
2013 - 2.4  source 
2012 - 2.3  source  
2011 - 2.4  source
2010 - 2.1  source
2009 - 2.6  source
2008 - 2.8  source

CALIFORNIA
FATAL WORK INJURIES RAW DATA
 (lower number is better)
2018 - 422  source (down 9% since 2008)
2017 - 376  source  *LEGALIZED
2016 - 376  source  (pop 39.21 million)
2015 - 388  source  
2014 - 344  source 
2013 - 396  source 
2012 - 375  source  
2011 - 390  source  
2010 - 326  source  
2009 - 409 source 
2008 - 465  source (pop 36.54 million)

CALIFORNIA
WORK ILLNESS AND INJURY INCIDENCE RATES PER CAPITA
 (lower number is better)
2018 - 3.6  source (down 18% since 2008)
2017 - 3.6  source *LEGALIZED
2016 - 3.7  source
2015 - 3.8  source
2014 -  3.8  source
2013 -  4.0  source 
2012 - 4.0  source
2011 - 4.0  source
2010 - 4.2  source
2009 - 4.2  source
2008 - 4.4  source