3M Scotch blue tape causes cancer or birth defects?

I notice on Amazon.com it comes with a California proposition 65 warning, but in the UK it has no special warnings anywhere. 

'California's Proposition 65 entitles California consumers to special warnings for products that contain chemicals known to the state of California to cause cancer and birth defects or other reproductive harm if those products expose consumers to such chemicals above certain threshold levels'

I have no idea what it is in the tape that could cause any problems, but have emailed 3M in the UK to ask them what its all about. I will add to this blog if and when I get answers.

Update 28/02/16

I have in the last 2 weeks managed to get some response from 3M, which you can read below

I ended up phoning them, due to a lack of response on at least 4 occasions!

Here's the email I received:

Hello Mr Brooks,
Firstly I must apologise for the totally unacceptable response time to your request dated December 19th 2015. We take all customer enquiries very seriously and I can only assume that with the holiday period and employee absences, your email was not responded to – my sincerest apologies once again.

Thank you for bringing to our attention the Proposition 65 warning placed on the ScotchBlue™ Tapes on Amazon.com. I have reached out to our US colleagues multiple times to try and find out why the product has been classified as such as we have been informed that Amazon do, on occasion, categorise products incorrectly. I have chased them as a matter of urgency on this matter this afternoon and will update you accordingly.

The ScotchBlue™ range of tapes are tested to be safe for use and there has been no connection to birth defects or carcinogens due to the extremely low level of chemicals included in the product.

Our laboratory have provided me with the following information:

ScotchBlue™ Tapes: when used under reasonable conditions and in accordance with the 3M directions for use, should not present a health hazard. However, use or processing of the product in a manner not in accordance with the product's directions for use may affect the performance of the product and may present potential health and safety hazards.

POTENTIAL HEALTH EFFECTS Eye Contact: Mechanical eye irritation: Signs/symptoms may include pain, redness, tearing and corneal abrasion. Skin Contact: Mechanical Skin irritation: Signs/symptoms may include abrasion, redness, pain, and itching. Inhalation: No health effects are expected. Ingestion: No health effects are expected.

I attach the Material Safety Data Sheet for the product which details any potential health effects associated with the product. This is a legal requirement and is available for public viewing on www.3m.com.

Once again, thank you for bringing this to our attention, I will ensure that my American colleagues work to amend this listing with Amazon to prevent any future concerns.

This week I received a second email:

Hi Craig,

We have had discussions with 3M in the US and we are able to confirm to you that there should not be a Prop 65 cancer statement for this 2090 product – 70006576493 - on Amazon Website. This is being updated with the 3M team in US and working with the update with the Amazon team.

Hope this information will reassure you whilst using 2090 Masking Tape.
Best regards